Conformational interdomain flexibility in a bacterial α-isopropylmalate synthase is necessary for leucine biosynthesis.

α-Isopropylmalate synthase (IPMS) catalyzes the first step in leucine (Leu) biosynthesis and is allosterically regulated by the pathway end product, Leu. IPMS is a dimeric enzyme with each chain consisting of catalytic, accessory, and regulatory domains, with the accessory and regulatory domains of each chain sitting adjacent to the catalytic domain of the other chain. The IPMS crystal structure shows significant asymmetry because of different relative domain conformations in each chain. Owing to the challenges posed by the dynamic and asymmetric structures of IPMS enzymes, the molecular details of their catalytic and allosteric mechanisms are not fully understood. In this study, we have investigated the allosteric feedback mechanism of the IPMS enzyme from the bacterium that causes meningitis, Neisseria meningitidis (NmeIPMS). By combining molecular dynamics simulations with small-angle X-ray scattering, mutagenesis, and heterodimer generation, we demonstrate that Leu-bound NmeIPMS is in a rigid conformational state stabilized by asymmetric interdomain polar interactions. Furthermore, we found removing these polar interactions by mutagenesis impaired the allosteric response without compromising Leu binding. Our results suggest that the allosteric inhibition of NmeIPMS is achieved by restricting the flexibility of the accessory and regulatory domains, demonstrating that significant conformational flexibility is required for catalysis.

Using a multi-stakeholder co-design process to develop a health service organisation-wide patient reported outcome measure collection system.

PURPOSE: Limited examples exist of successful Patient Reported Outcome Measure (PROM) implementation across an entire healthcare organisation. The aim of this study was to use a multi-stakeholder co-design process to develop a PROM collection system, which will inform implementation of routine collection of PROMs across an entire healthcare organisation. METHODS: Co-design comprised semi-structured interviews with clinicians (n = 11) and workshops/surveys with consumers (n = 320). The interview guide with clinicians focused on their experience using PROMs, preferences for using PROMs, and facilitators/barriers to using PROMs. Co-design activities specific to consumers focused on: (1) how PROMs will be administered (mode), (2) when PROMs will be administered (timing), (3) who will assist with PROMs collection, and (4) how long a PROM will take to complete. Data were analysed using a manifest qualitative content analysis approach. RESULTS: Core elements identified during the co-design process included: PROMs collection should be consumer-led and administered by someone other than a clinician; collection at discharge from the healthcare organisation and at 3-6 months post discharge would be most suitable for supporting comprehensive assessment; PROMs should be administered using a variety of modes to accommodate the diversity of consumer preferences, with electronic as the default; and the time taken to complete PROMs should be no longer than 5-10 min. CONCLUSION: This study provides new information on the co-design of a healthcare organisation-wide PROM collection system. Implementing a clinician and patient informed strategy for PROMs collection, that meets their preferences across multiple domains, should address known barriers to routine collection.

Generation of Alternate Indole Diterpene Architectures in Two Species of Aspergilli.

The significant structural diversity and potent bioactivity of the fungal indole diterpenes (IDTs) has attracted considerable interest in their biosynthesis. Although substantial skeletal diversity is generated by the action of noncanonical terpene cyclases, comparatively little is known about these enzymes, particularly those involved in the generation of the subgroup containing emindole SA and DA, which show alternate terpenoid skeletons. Here, we describe the IDT biosynthetic machinery generating these unusual IDT architectures from Aspergillus striatus and Aspergillus desertorum. The function of four putative cyclases was interrogated via heterologous expression. Two specific cyclases were identified that catalyze the formation of epimers emindole SA and DA from A. striatus and A. desertorum, respectively. These cyclases are both clustered along with all the elements required for basic IDT biosynthesis yet catalyze an unusual Markovnikov-like cyclization cascade with alternate stereochemical control. Their identification reveals that these alternate architectures are not generated by mechanistically sloppy or promiscuous enzymes, but by cyclases capable of delivering precise regio- and stereospecificities.

A landscape assessment of the use of patient reported outcome measures in research, quality improvement and clinical care across a healthcare organisation.

BACKGROUND: Patient reported outcome measures (PROMs) can be used by healthcare organisations to inform improvements in service delivery. However, routine collection of PROMs is difficult to achieve across an entire healthcare organisation. An understanding of the use of PROMs within an organisation can provide valuable insights on the purpose, scope and practical considerations of PROMs collection, which can inform implementation of PROMs. METHODS: We used multiple research methods to assess the use of PROMs in research projects, data registries and clinical care across a healthcare organisation from January 2014 to April 2021. The methods included an audit of ethics applications approved by the organisation's human research ethics committee and registries which the health organisation had contributed data to; a literature review of peer-reviewed journal articles reporting on research projects conducted at the organisation; and a survey of health professionals use of PROMs in research projects, data registries and clinical care. The scope of PROMs was determined by classifying PROMs as either 'specific' to a particular disease and/or condition, or as a 'generic' measure with further classification based on the health domains they measured, using the World Health Organization International Classification Framework. Practical considerations included mode and timing of PROMs administration. Data were described using frequency and proportion. RESULTS: PROMs were used by 22% of research projects (n = 144/666), 68% of data registries (n = 13/19), and 76% of clinical specialties in their clinical care (n = 16/21). Disease specific PROMs were most commonly used: 83% of research projects (n = 130/144), 69% of clinical registries (n = 9/13), and 75% of clinical specialties (n = 12/16). Greater than 80% of research projects, clinical registries and clinical specialties measured health domains relating to both body impairments and participation in daily life activities. The most commonly used generic PROM was the EQ-5D (research projects n = 56/144, 39%; data registries n = 5/13, 38%; clinical specialties n = 4/16, 25%). PROMs used in clinical care were mostly paper-based (n = 47/55, 85%). CONCLUSIONS: We have elicited information on the use of PROMs to inform a health organisation wide implementation strategy. Future work will determine clinician and patient acceptability of the EQ-5D, and co-design a system for the collection of PROMs.

American Orthopaedic Foot and Ankle Society Annual Meeting All-in-person Attendance Results in Immense Carbon Expenditure.

BACKGROUND: Professional society conferences are integral to the medical profession. However, airline travel is a major contributor to greenhouse gas production, and the environmental impact of in-person attendance at an orthopaedic conference has yet to be described. With growing concern about the climate crisis, we sought to quantify the carbon footprint of in-person attendance to help potential attendees more consciously consider in-person attendance, inform strategies to minimize greenhouse gas emissions during travel to annual meetings, and increase awareness about and momentum for efforts in orthopaedic surgery to reduce the carbon footprint of society conferences. QUESTIONS/PURPOSES: (1) What was the magnitude of greenhouse gas production resulting from all-in-person 2019 American Orthopaedic Foot and Ankle Society (AOFAS) annual meeting attendance in Chicago, IL, USA? (2) What was the magnitude of greenhouse gas production resulting from the all-virtual 2020 AOFAS annual meeting, and how does it compare with the 2019 AOFAS annual meeting carbon footprint? (3) To what extent could an alternative in-person meeting model with four or seven hubs decrease greenhouse gas production resulting from round-trip air travel compared with the 2019 AOFAS annual meeting? METHODS: A list of the postal codes and countries of all 1271 registered participants attending the four-day 2019 AOFAS annual meeting in Chicago, IL, USA, was obtained from AOFAS headquarters. The 2019 conference was chosen because it was the last pre-COVID meeting and thus attendance was more likely to resemble that at prepandemic in-person conferences than more recent meetings because of pandemic travel restrictions. We estimated carbon dioxide-equivalent (CO 2 e) production from round-trip air travel using a publicly available internet-based calculator (Myclimate: https://co2.myclimate.org/en/flight_calculators/new ). Emissions produced by the conference venue, car travel, and hotel stays were estimated using published Environmental Protection Agency emission factors. To estimate emissions produced by the all-virtual 2020 AOFAS annual meeting (assuming an equal number of attendees as in 2019), we used the framework published by Faber and summed estimated network data transfer emissions, personal computer and monitor emissions, and server-related emissions. Using the 2019 registrant list, we modeled four-hub and seven-hub in-person meeting alternatives to determine potential decreased round-trip air travel greenhouse gas production. Meeting hub locations were selected by visualizing the geographic distribution of the 2019 registrants and selecting reasonable meeting locations that would minimize air travel for the greatest number of attendees. Registrants were assigned to the nearest hub location. Myclimate was again used to estimate CO 2 e production for round-trip air travel for the hub meeting models. RESULTS: The total estimated emissions of the all-in-person 2019 AOFAS annual meeting (when accounting for travel, conference space, and hotel stays) was 1565 tons CO 2 e (median 0.61 tons per attendee, range 0.02 to 7.7 tons). The total estimated emissions of the all-virtual 2020 meeting (when accounting for network data transfer emissions, personal computer and monitor emissions, and server-related emissions) was 34 tons CO 2 e (median 0.03 tons per attendee). This corresponds to a 97.8% decrease in CO 2 e emissions compared with the in-person conference. The model of a four-hub in-person meeting alternative with meetings in Chicago, Santiago, London, and Tokyo predicted an estimated 54% decrease in CO 2 e emissions from round-trip air travel. The seven-hub meeting model with meetings in Chicago; Washington, DC; Dallas; Los Angeles; Santiago; London; and Tokyo was predicted to diminish the CO 2 e emissions of round-trip air travel by an estimated 71%. CONCLUSION: The 2019 AOFAS annual meeting had an enormous carbon footprint and resulted in many individuals exceeding their annual allotted carbon budget (2.5 tons) according to the Paris Agreement. Hosting the meeting virtually greatly reduced the annual meeting carbon footprint, and our hub-based meeting models identified potential in-person alternatives for reducing the carbon footprint of conference attendance. CLINICAL RELEVANCE: Professional societies must consider our responsibility to decarbonizing the healthcare sector by considering innovative approaches-perhaps such as our multihub proposals-to decarbonize carbon-intensive annual meetings without stalling academic progress.

Precise Positioning of Water Is Critical for Hydrolysis Catalyzed by 5'-Methylthioadenosine Nucleosidase.

Enzyme-catalyzed hydrolysis is a fundamental chemical transformation involved in many essential metabolic processes. The enzyme 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) catalyzes the hydrolysis of adenosine-containing metabolites in cysteine and methionine metabolism. Although MTAN enzymes contain highly similar active site architecture and generally follow a dissociative (DN*AN) reaction mechanism, substantial differences in reaction rates and chemical transition state structures have been reported. To understand how subtle changes in sequence and structure give rise to differences in chemistry between homologous enzymes, we have probed the reaction coordinates of two MTAN enzymes using quantum mechanical/molecular mechanical and molecular dynamics simulations combined with experimental methods. We show that the transition state structure and energy are significantly affected by the recruitment and positioning of the catalytic water molecule and that subtle differences in the noncatalytic active site residues alter the environment of the catalytic water, leading to changes in the reaction coordinate and observed reaction rate.

MicroRNA cargo of extracellular vesicles released by skeletal muscle fibro-adipogenic progenitor cells is significantly altered with disuse atrophy and IL-1ß deficiency.

Fibro-adipogenic progenitor cells (FAPs) are a population of stem cells in skeletal muscle that play multiple roles in muscle repair and regeneration through their complex secretome; however, it is not well understood how the FAP secretome is altered with muscle disuse atrophy. Previous work suggests that the inflammatory cytokine IL-1ß is increased in FAPs with disuse and denervation. Inflammasome activation and IL-1ß secretion are also known to stimulate the release of extracellular vesicles (EVs). Here, we examined the microRNA (miRNA) cargo of FAP-derived, platelet-derived growth factor receptor A (PDGFRα+) EVs from hindlimb muscles of wild-type and IL-1ß KO mice after 14 days of single-hindlimb immobilization. Hindlimb muscles were isolated from mice following the immobilization period, and PDGFRα+ extracellular vesicles were isolated using size-exclusion chromatography and immunoprecipitation. Microarrays were performed to detect changes in miRNAs with unloading and IL-1ß deficiency. Results indicate that the PDGFRα+, FAP-derived EVs show a significant increase in miRNAs, such as miR-let-7c, miR-let-7b, miR-181a, and miR-124. These miRNAs have previously been demonstrated to play important roles in cellular senescence and muscle atrophy. Furthermore, the expression of these same miRNAs was not significantly altered in FAP-derived EVs isolated from the immobilized IL-1ß KO. These data suggest that disuse-related activation of IL-1ß can mediate the miRNA cargo of FAP-derived EVs, contributing directly to the release of senescence- and atrophy-related miRNAs. Therapies targeting FAPs in settings associated with muscle disuse atrophy may therefore have the potential to preserve muscle function and enhance muscle recovery.

Reciprocal allostery arising from a bienzyme assembly controls aromatic amino acid biosynthesis in Prevotella nigrescens.

Modular protein assembly has been widely reported as a mechanism for constructing allosteric machinery. Recently, a distinctive allosteric system has been identified in a bienzyme assembly comprising a 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS) and chorismate mutase (CM). These enzymes catalyze the first and branch point reactions of aromatic amino acid biosynthesis in the bacterium Prevotella nigrescens (PniDAH7PS), respectively. The interactions between these two distinct catalytic domains support functional interreliance within this bifunctional enzyme. The binding of prephenate, the product of CM-catalyzed reaction, to the CM domain is associated with a striking rearrangement of overall protein conformation that alters the interdomain interactions and allosterically inhibits the DAH7PS activity. Here, we have further investigated the complex allosteric communication demonstrated by this bifunctional enzyme. We observed allosteric activation of CM activity in the presence of all DAH7PS substrates. Using small-angle X-ray scattering (SAXS) experiments, we show that changes in overall protein conformations and dynamics are associated with the presence of different DAH7PS substrates and the allosteric inhibitor prephenate. Furthermore, we have identified an extended interhelix loop located in CM domain, loopC320-F333, as a crucial segment for the interdomain structural and catalytic communications. Our results suggest that the dual-function enzyme PniDAH7PS contains a reciprocal allosteric system between the two enzymatic moieties as a result of this bidirectional interdomain communication. This arrangement allows for a complex feedback and feedforward system for control of pathway flux by connecting the initiation and branch point of aromatic amino acid biosynthesis.

Lessons Learned in Implementing Patient-Reported Outcome Measures (PROMs) in the Australian Breast Device Registry (ABDR).

BACKGROUND: The Australian Breast Device Registry (ABDR) is a clinical quality registry which utilizes both surgical data and patient-reported outcome measures (PROMs) to understand device performance. The ABDR is the first national breast device registry utilizing the BREAST-Q Implant Surveillance module to conduct PROMs via text messaging as the primary method of contact for most patients. ABDR PROMs are structured upon a successful acceptability and feasibility study and a pilot study. OBJECTIVES: This aim of this paper was to examine the challenges we faced and consider how lessons learned in implementing PROMs might inform future registry studies and interventions. METHODS: We tracked the number of completed follow-ups and documented feedback between October 2017 and December 2018 from various stakeholders, including sites, surgeons, and patients. RESULTS: In total, 10,617 patients were contacted: 59% of breast augmentation and 77% breast reconstruction patients responded to our PROMs survey. We encountered challenges and developed solutions to overcome several key issues, including database setup; follow-up contact methods; ethics; education of surgeons and patients; associated costs; and ongoing evaluation and modification. The strategies we devised to address these challenges included drawing on experiences from previous studies, greater communication with sites and surgeons, and having the flexibility to improve and modify our PROMs. CONCLUSIONS: The ABDR PROMs experience and lessons learned can inform a growing number of registries seeking to conduct PROMs. We describe our approach, obstacles encountered, and strategies to increase patient participation. As more breast device registries worldwide adopt PROMs, data harmonization is crucial to better understand patient outcomes and device performance.

Biosynthesis of Nodulisporic Acids: A Multifunctional Monooxygenase Delivers a Complex and Highly Branched Array.

Nodulisporic acids (NAs) are structurally complex potent antiinsectan indole diterpenes. We previously reported the biosynthetic gene cluster for these metabolites in Hypoxylon pulicicidum and functionally characterised the first five steps of the biosynthetic pathway. Here we reveal a highly complex biosynthetic array, furnishing multiple end products through expression of cluster components in Penicillium paxilli. We show that seven additional cluster-encoded gene products comprise the biosynthetic machinery that elaborate precursor NAF in this highly branched pathway. The combined action of these enzymes delivers 37 NA congeners including four major end products, NAA, NAA1 , NAA2 and NAA4 . The plethora of intermediates arises due to modification of the carboxylated prenyl tail by a single promiscuous P450 monooxygenase, NodJ, a pivotal branchpoint enzyme which produces four distinct biosynthetic products giving rise to the complex metabolic grid that characterises NA biosynthesis.

A single amino acid substitution uncouples catalysis and allostery in an essential biosynthetic enzyme in Mycobacterium tuberculosis.

Allostery exploits the conformational dynamics of enzymes by triggering a shift in population ensembles toward functionally distinct conformational or dynamic states. Allostery extensively regulates the activities of key enzymes within biosynthetic pathways to meet metabolic demand for their end products. Here, we have examined a critical enzyme, 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS), at the gateway to aromatic amino acid biosynthesis in Mycobacterium tuberculosis, which shows extremely complex dynamic allostery: three distinct aromatic amino acids jointly communicate occupancy to the active site via subtle changes in dynamics, enabling exquisite fine-tuning of delivery of these essential metabolites. Furthermore, this allosteric mechanism is co-opted by pathway branchpoint enzyme chorismate mutase upon complex formation. In this study, using statistical coupling analysis, site-directed mutagenesis, isothermal calorimetry, small-angle X-ray scattering, and X-ray crystallography analyses, we have pinpointed a critical node within the complex dynamic communication network responsible for this sophisticated allosteric machinery. Through a facile Gly to Pro substitution, we have altered backbone dynamics, completely severing the allosteric signal yet remarkably, generating a nonallosteric enzyme that retains full catalytic activity. We also identified a second residue of prime importance to the inter-enzyme communication with chorismate mutase. Our results reveal that highly complex dynamic allostery is surprisingly vulnerable and provide further insights into the intimate link between catalysis and allostery.

Limited Bacterial Removal in Full-Scale Stormwater Biofilters as Evidenced by Community Sequencing Analysis.

In urban areas, untreated stormwater runoff can pollute downstream surface waters. To intercept and treat runoff, low-impact or "green infrastructure" approaches such as using biofilters are adopted. Yet, actual biofilter pollutant removal is poorly understood; removal is often studied in laboratory columns, with variable removal of viable and culturable microbial cell numbers including pathogens. Here, to assess bacterial pollutant removal in full-scale planted biofilters, stormwater was applied, unspiked or spiked with untreated sewage, in simulated storm events under transient flow conditions, during which biofilter influents versus effluents were compared. Based on microbial biomass, sequences of bacterial community genes encoding 16S rRNA, and gene copies of the human fecal marker HF183 and of the Enterococcus spp. marker Entero1A, removal of bacterial pollutants in biofilters was limited. Dominant bacterial taxa were similar for influent versus effluent aqueous samples within each inflow treatment of either spiked or unspiked stormwater. Bacterial pollutants in soil were gradually washed out, albeit incompletely, during simulated storm flushing events. In post-storm biofilter soil cores, retained influent bacteria were concentrated in the top layers (0-10 cm), indicating that the removal of bacterial pollutants was spatially limited to surface soils. To the extent that plant-associated processes are responsible for this spatial pattern, treatment performance might be enhanced by biofilter designs that maximize influent contact with the rhizosphere.

Exploring modular allostery via interchangeable regulatory domains.

Most proteins comprise two or more domains from a limited suite of protein families. These domains are often rearranged in various combinations through gene fusion events to evolve new protein functions, including the acquisition of protein allostery through the incorporation of regulatory domains. The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) is the first enzyme of aromatic amino acid biosynthesis and displays a diverse range of allosteric mechanisms. DAH7PSs adopt a common architecture with a shared (ß/α)8 catalytic domain which can be attached to an ACT-like or a chorismate mutase regulatory domain that operates via distinct mechanisms. These respective domains confer allosteric regulation by controlling DAH7PS function in response to ligand Tyr or prephenate. Starting with contemporary DAH7PS proteins, two protein chimeras were created, with interchanged regulatory domains. Both engineered proteins were catalytically active and delivered new functional allostery with switched ligand specificity and allosteric mechanisms delivered by their nonhomologous regulatory domains. This interchangeability of protein domains represents an efficient method not only to engineer allostery in multidomain proteins but to create a new bifunctional enzyme.

Identification of Estrogen Signaling in a Prioritization Study of Intraocular Pressure-Associated Genes.

Elevated intraocular pressure (IOP) is the only modifiable risk factor for primary open-angle glaucoma (POAG). Herein we sought to prioritize a set of previously identified IOP-associated genes using novel and previously published datasets. We identified several genes for future study, including several involved in cytoskeletal/extracellular matrix reorganization, cell adhesion, angiogenesis, and TGF-ß signaling. Our differential correlation analysis of IOP-associated genes identified 295 pairs of 201 genes with differential correlation. Pathway analysis identified ß-estradiol as the top upstream regulator of these genes with ESR1 mediating 25 interactions. Several genes (i.e., EFEMP1, FOXC1, and SPTBN1) regulated by ß-estradiol/ESR1 were highly expressed in non-glaucomatous human trabecular meshwork (TM) or Schlemm's canal (SC) cells and specifically expressed in TM/SC cell clusters defined by single-cell RNA-sequencing. We confirmed ESR1 gene and protein expression in human TM cells and TM/SC tissue with quantitative real-time PCR and immunofluorescence, respectively. 17ß-estradiol was identified in bovine, porcine, and human aqueous humor (AH) using ELISA. In conclusion, we have identified estrogen receptor signaling as a key modulator of several IOP-associated genes. The expression of ESR1 and these IOP-associated genes in TM/SC tissue and the presence of 17ß-estradiol in AH supports a role for estrogen signaling in IOP regulation.

Drink driving during the COVID-19 pandemic.

Due to the COVID-19 pandemic, static roadside random breath testing (RBT) was temporarily suspended between 16 March and 12 June 2020 in Queensland, Australia. In addition to restrictions on travel and social interactions, this provided a unique opportunity to examine changes in drink-driving behaviour during and after a reduction in RBT operations in the community. Three cross-sectional surveys were disseminated at different time points to examine these differences. Over three surveys, 1193 Queensland licensed drivers aged 18 years and over (M = 36.9, SD = 16.7) responded. While overall drink driving decreased over the three survey periods, there were groups where drink driving, or the intention to drink drive, increased over the same period. The overall decrease could be expected as a result of community restrictions on socialising and travel behaviours. In each of the surveys, prior engagement in drink driving was the strongest predictor of intention to increase future engagement and actual engagement. These drink drivers were more likely aged 18-24 years, male, and held restricted licensure. Notably, a small number of participants who reported drink driving, and/or intention to drink drive during the survey period, reported not having engaged in this behaviour previously. This suggested an increased likelihood of drink drivers experiencing punishment avoidance which may promote future engagement in this behaviour. Despite a decrease in social opportunities to drink, and the suspension of highly visible roadside breath testing sites, drink driving persisted. This research highlights the importance of RBTs as a general deterrent for drink driving.

Test-Retest Reliability of the BREAST-Q IS in the Australian Breast Device Registry.

BACKGROUND: Patient-reported outcome measures (PROMs) are increasingly employed in healthcare to assess outcomes. The BREAST-Q Implant Surveillance module (BREAST-Q IS) is a 5-question PROM utilized by the Australian Breast Device Registry to monitor the performance of breast devices. Validation of this tool is needed to assess its utility in this setting. OBJECTIVES: The objective of this study was to assess the test-retest reliability of the BREAST-Q IS among breast implant recipients within a registry setting. METHODS: A test-retest reliability study was undertaken. Patients who underwent breast augmentation or breast reconstruction and registered with the Australian Breast Device Registry were eligible to participate. A total of 250 surveys were distributed. The BREAST-Q IS was administered to the same group of participants on 2 separate occasions with a 2-week test interval. Participants were divided into 2 groups: breast augmentation and breast reconstruction. A weighted kappa coefficient was calculated to assess the degree of test-retest reliability of the BREAST-Q IS. RESULTS: A total of 207 participants completed both tests. The response rate was 82% (n = 113) for the breast augmentation group and 94% (n = 94) for the breast reconstruction group. All 5 questions on the BREAST-Q IS obtained weighted kappa scores above 0.74 among both groups. CONCLUSIONS: The BREAST-Q IS has good to excellent test-retest reliability for utilization among breast implant recipients in a registry setting. Further validation of the BREAST-Q IS will be required to establish the BREAST-Q IS as a valid and reliable PROM tool for breast implant recipients following breast device surgery.

Domain cross-talk within a bifunctional enzyme provides catalytic and allosteric functionality in the biosynthesis of aromatic amino acids.

Because of their special organization, multifunctional enzymes play crucial roles in improving the performance of metabolic pathways. For example, the bacterium Prevotella nigrescens contains a distinctive bifunctional protein comprising a 3-deoxy-d-arabino heptulosonate-7-phosphate synthase (DAH7PS), catalyzing the first reaction of the biosynthetic pathway of aromatic amino acids, and a chorismate mutase (CM), functioning at a branch of this pathway leading to the synthesis of tyrosine and phenylalanine. In this study, we characterized this P. nigrescens enzyme and found that its two catalytic activities exhibit substantial hetero-interdependence and that the separation of its two distinct catalytic domains results in a dramatic loss of both DAH7PS and CM activities. The protein displayed a unique dimeric assembly, with dimerization solely via the CM domain. Small angle X-ray scattering (SAXS)-based structural analysis of this protein indicated a DAH7PS-CM hetero-interaction between the DAH7PS and CM domains, unlike the homo-association between DAH7PS domains normally observed for other DAH7PS proteins. This hetero-interaction provides a structural basis for the functional interdependence between the two domains observed here. Moreover, we observed that DAH7PS is allosterically inhibited by prephenate, the product of the CM-catalyzed reaction. This allostery was accompanied by a striking conformational change as observed by SAXS, implying that altering the hetero-domain interaction underpins the allosteric inhibition. We conclude that for this C-terminal CM-linked DAH7PS, catalytic function and allosteric regulation appear to be delivered by a common mechanism, revealing a distinct and efficient evolutionary strategy to utilize the functional advantages of a bifunctional enzyme.

Medically actionable pathogenic variants in a population of 13,131 healthy elderly individuals.

PURPOSE: To measure the prevalence of medically actionable pathogenic variants (PVs) among a population of healthy elderly individuals. METHODS: We used targeted sequencing to detect pathogenic or likely pathogenic variants in 55 genes associated with autosomal dominant medically actionable conditions, among a population of 13,131 individuals aged 70 or older (mean age 75 years) enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) trial. Participants had no previous diagnosis or current symptoms of cardiovascular disease, physical disability or dementia, and no current diagnosis of life-threatening cancer. Variant curation followed American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) standards. RESULTS: One in 75 (1.3%) healthy elderly individuals carried a PV. This was lower than rates reported from population-based studies, which have ranged from 1.8% to 3.4%. We detected 20 PV carriers for Lynch syndrome (MSH6/MLH1/MSH2/PMS2) and 13 for familial hypercholesterolemia (LDLR/APOB/PCSK9). Among 7056 female participants, we detected 15 BRCA1/BRCA2 PV carriers (1 in 470 females). We detected 86 carriers of PVs in lower-penetrance genes associated with inherited cardiac disorders. CONCLUSION: Medically actionable PVs are carried in a healthy elderly population. Our findings raise questions about the actionability of lower-penetrance genes, especially when PVs are detected in the absence of symptoms and/or family history of disease.

Hinge Twists and Population Shifts Deliver Regulated Catalysis for ATP-PRT in Histidine Biosynthesis.

Allosteric regulation plays an important role in the control of metabolic flux in biosynthetic pathways. In microorganisms, many enzymes in these pathways adopt different strategies of allostery to allow the tuning of their activities in response to metabolic demand. Thus, it is important to uncover the mechanism of allosteric signal transmission to fully comprehend the complex control of enzyme function and its evolution. ATP-phosphoribosyltransferase (ATP-PRT), as the first enzyme in the histidine biosynthetic pathway, is allosterically regulated by histidine and offers a good platform for the study of allostery. Two forms of ATP-PRT, namely long and short forms, were discovered that show different arrangements of their regulatory machinery. Crystal structures of the long-form ATP-PRT have revealed overall conformational changes in the inhibited state, but the observed changes in the active state are quite subtle, making the elucidation of its allosteric mechanism difficult. Here, we combine computational methods (ligand docking, quantum mechanics/molecular mechanics optimization, and molecular dynamic simulations) with experimental studies to probe the signal transmission between remote allosteric and active sites. Our results reveal that distinct conformational ensembles of the catalytic domain with different dynamic properties exist in the ligand-free and histidine-bound enzymes. These ensembles display different capabilities in supporting the catalytic and allosteric function of ATP-PRT. The findings give insight into the underlying mechanism of allostery and allow us to propose that the hinge twisting within the catalytic domain is the key for both enhancement of catalysis and provision of regulation in ATP-PRT enzymes.

Comparison of healthcare resource utilization and costs in patients with type 2 diabetes initiating dapagliflozin versus sitagliptin.

AIMS: To compare healthcare costs and utilization in patients with type 2 diabetes (T2D) who initiated dapagliflozin (DAPA) with costs and utilization in those who initiated sitagliptin (SITA) in a real-world setting. MATERIALS AND METHODS: This was a retrospective study of health plan enrollees in two US commercial claims databases or Medicare Part D. The study population comprised adult patients with T2D who initiated DAPA or SITA between January 1, 2014 and April 30, 2015. DAPA and SITA initiators were propensity-score-matched, and healthcare utilization and costs during the 1-year follow-up period were compared. Analyses were conducted separately for patients with evidence of oral antidiabetic drug (OAD) monotherapy use at baseline. RESULTS: A total of 2722 patients were included in each matched cohort. Follow-up unadjusted all-cause costs ($16 065 and $17 281; P = 0.135) and diabetes-related costs ($9697 and $9354; P = 0.539) were similar in the DAPA and SITA cohorts. Higher office and outpatient visit costs in the SITA group were offset by higher pharmacy costs in the DAPA group. In the subgroup of 1804 patients with OAD monotherapy use at baseline, patients in the SITA group had higher total all-cause costs compared with those in the DAPA group ($14 884 vs. $12 353; P = 0.026). CONCLUSION: Patients who initiated DAPA or SITA had similar all-cause and diabetes-related healthcare costs over 1 year of follow-up. In the subgroup of patients treated with OAD monotherapy at baseline (84% metformin monotherapy), those who initiated DAPA as add-on therapy had lower costs than patients who added SITA.