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1.
Nurs Health Sci ; 26(2): e13114, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38566419

ABSTRACT

The purpose of this study was to evaluate the handoff guidance (HG) self-management intervention for multimorbid chronic obstructive pulmonary disease (COPD) patients following hospitalization for acute exacerbation of COPD (AECOPD) using HG self-management intervention compared to a control group on COPD self-management outcomes (self-care, self-efficacy, health engagement) and assess feasibility, acceptability, and healthcare utilization. A randomized pilot study used a 2-group with repeated measures design. Adults with COPD who had been hospitalized for AECOPD were recruited. After discharge, the HG self-management intervention employed health coaching delivered at: 1-3, 10-12, and 20-22 days after hospital discharge. Follow-up data collected was collected at 1-3, 10-12, 20-22, 30, 60, and 90 days after hospital discharge. A total of 29 subjects participated, with a mean age of 66 (+8.7) years old, the majority were females (n = 18). Intervention participants reported the acceptability of the HG self-management intervention. Participants in both groups continued to report COPD symptoms after discharge, which decreased over time, although not significantly different by group. The use of COPD maintenance, monitoring, and management behaviors was higher in the treatment group, although not significantly different.


Subject(s)
Pulmonary Disease, Chronic Obstructive , Self-Management , Adult , Female , Humans , Aged , Child , Male , Pilot Projects , Hospitalization , Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/therapy , Patient Discharge , Disease Progression
2.
Adv Clin Chem ; 117: 103-161, 2023.
Article in English | MEDLINE | ID: mdl-37973318

ABSTRACT

Preeclampsia is a multisystem hypertensive disorder and one of the leading causes of maternal and fetal morbidity and mortality. The clinical hallmarks such as hypertension and proteinuria, and additional laboratory tests currently available including liver enzyme testing, are neither specific nor sufficiently sensitive. Therefore, biomarkers for timely and accurate identification of patients at risk of developing preeclampsia are extremely valuable to improve patient outcomes and safety. In this chapter, we will first discuss the clinical characteristics of preeclampsia and current evidence of the role of angiogenic factors, such as placental growth factor (PlGF) and soluble FMS like tyrosine kinase 1 (sFlt-1) in the pathogenesis of preeclampsia. Second, we will review the clinical practice guidelines for preeclampsia diagnostic criteria and their recommendations on laboratory testing. Third, we will review the currently available PlGF and sFlt-1 assays in terms of their methodologies, analytical performance, and clinical diagnostic values. Finally, we will discuss the future research needs from both an analytical and clinical perspective.


Subject(s)
Hypertension , Pre-Eclampsia , Pregnancy , Humans , Female , Pre-Eclampsia/diagnosis , Placenta Growth Factor , Biomarkers , Vascular Endothelial Growth Factor A
3.
West J Nurs Res ; 45(12): 1165-1172, 2023 12.
Article in English | MEDLINE | ID: mdl-37905515

ABSTRACT

The purpose of this systematic review was to identify evidence pertaining to the effectiveness of behavioral weight loss interventions for overweight and obese cardiac rehabilitation participants. A database search of PUBMED, CINAHL, PsycINFO, and PROSPERO yielded 10 eligible studies. Quantitative studies implementing behavioral weight loss interventions for overweight and obese adult cardiac rehabilitation participants were reviewed. Evidence supported the usefulness and effectiveness of behavioral weight loss interventions for overweight cardiac rehabilitation participants. With the limited number of studies and inclusion of quasi-experimental studies with comparative groups, it was not possible to determine the relative power of behavioral weight loss interventions across studies. In conclusion, behavioral weight loss interventions can be incorporated into cardiac rehabilitation or offered following cardiac rehabilitation to improve weight loss of overweight and obese cardiac rehabilitation participants. Findings reinforce national guidelines emphasizing the role of cardiac rehabilitation to address secondary cardiovascular disease risk factor modification, including integrating behavioral weight loss programs in cardiac rehabilitation, or referring overweight patients to weight management programs following completion of cardiac rehabilitation.


Subject(s)
Cardiac Rehabilitation , Overweight , Adult , Humans , Overweight/complications , Overweight/therapy , Obesity/complications , Obesity/therapy , Weight Loss
4.
J Appl Lab Med ; 8(5): 856-870, 2023 09 07.
Article in English | MEDLINE | ID: mdl-37473432

ABSTRACT

BACKGROUND: Vitamin D supplementation is common practice for neonates and infants due to limited stores of vitamin D at birth. Although not commonly encountered, vitamin D toxicity can occur due to over-supplementation. However, toxic concentrations are often not included in method validation experiments, and assays often are not validated in the neonatal population. METHODS: We compared serial 25 hydroxy vitamin D [25(OH)D] measurements in pre-term neonates receiving 25(OH)D supplementation and identified 12 patients wherein concentrations of 25(OH)D were above 50 ng/mL (125 nM) that required additional investigations as the 25(OH)D results did not match the clinical picture. Available samples were compared across 4 immunoassay platforms (LIAISON XL, Roche Cobas e602, Abbott Alinity i, and Siemens Centaur XP) and LC-MS/MS. RESULTS: Concentrations of 25(OH)D observed on one individual immunoassay platform (LIAISON XL) fluctuated substantially between subsequent blood draws in select neonates with elevated concentrations. Serum samples from these patients showed variable agreement between LC-MS/MS and other immunoassay platforms. These fluctuations were not explained by the presence of 3-epimer-25(OH)D or 24,25(OH)2D. CONCLUSIONS: Although we were unable to identify a cause for the variable elevated results, our findings suggest that neonatal 25(OH)D measurements alone should not be used for assessment of nutritional monitoring, and that clinical correlation and other laboratory parameters including ionized calcium should be considered.


Subject(s)
Tandem Mass Spectrometry , Vitamin D , Infant, Newborn , Humans , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Immunoassay/methods , Laboratories
5.
J Inorg Biochem ; 242: 112164, 2023 05.
Article in English | MEDLINE | ID: mdl-36871418

ABSTRACT

The p53 protein, known as the 'guardian of the genome', plays an important role in cancer prevention. Unfortunately, p53 mutations result in compromised activity with over 50% of cancers resulting from point mutations to p53. There is considerable interest in mutant p53 reactivation, with the development of small-molecule reactivators showing promise. We have focused our efforts on the common p53 mutation Y220C, which causes protein unfolding, aggregation, and can result in the loss of a structural Zn from the DNA-binding domain. In addition, the Y220C mutant creates a surface pocket that can be stabilized using small molecules. We previously reported the bifunctional ligand L5 as a Zn metallochaperone and reactivator of the p53-Y220C mutant. Herein we report two new ligands L5-P and L5-O that are designed to act as Zn metallochaperones and non-covalent binders in the Y220C mutant pocket. For L5-P the distance between the Zn-binding di-(2-picolyl)amine function and the pocket-binding diiodophenol was extended in comparison to L5, while for L5-O we extended the pocket-binding moiety via attachment of an alkyne function. While both new ligands displayed similar Zn-binding affinity to L5, neither acted as efficient Zn-metallochaperones. However, the new ligands exhibited significant cytotoxicity in the NCI-60 cell line screen as well as in the NUGC3 Y220C mutant cell line. We identified that the primary mode of cytotoxicity is likely reactive oxygen species (ROS) generation for L5-P and L5-O, in comparison to mutant p53 reactivation for L5, demonstrating that subtle changes to the ligand scaffold can change the toxicity pathway.


Subject(s)
Metallochaperones , Tumor Suppressor Protein p53 , Metallochaperones/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ligands , Cell Line, Tumor , Protein Domains
6.
J Appl Lab Med ; 8(3): 457-468, 2023 05 04.
Article in English | MEDLINE | ID: mdl-36869760

ABSTRACT

BACKGROUND: Preeclampsia is a multisystem disorder defined by new onset of hypertension with proteinuria after 20 weeks gestation. In part due to dysregulation of pro-angiogenic factors (e.g., placental growth factor [PlGF]) and anti-angiogenic factors (e.g., soluble fms-like tyrosine kinase 1 [sFlt-1]), preeclampsia results in decreased placental perfusion. An increased sFlt-1:PlGF ratio is associated with increased risk of preeclampsia. In this study, we evaluated sFlt-1:PlGF cutoffs and evaluated the clinical performance of sFlt-1:PlGF for predicting preeclampsia. METHODS: sFlt-1:PlGF results from 130 pregnant females with clinical suspicion of preeclampsia were used to evaluate the diagnostic accuracy of different sFlt-1:PlGF cutoffs and to compare the clinical performance of sFlt-1:PlGF to traditional preeclampsia markers (proteinuria and hypertension). Serum sFlt-1 and PlGF were measured using Elecsys immunoassays (Roche Diagnostics) and preeclampsia diagnosis was verified by expert chart review. RESULTS: A sFlt-1:PlGF cutoff of >38 yielded the greatest diagnostic accuracy of 90.8% (95% CI, 85.8%-95.7%). Using a cutoff of >38, sFlt-1:PlGF exhibited a greater diagnostic accuracy than traditionally used parameters such as new or worsening proteinuria or hypertension (71.9% and 68.6%, respectively). sFlt-1:PlGF >38 exhibited a negative predictive value (NPV) of 96.4% for rule-out of preeclampsia within 7 days, and a positive predictive value (PPV) of 84.8% for predicting preeclampsia within 28 days. CONCLUSIONS: Our study shows the superior clinical performance of sFlt-1:PlGF over hypertension and proteinuria alone to predict preeclampsia at a high-risk obstetrical unit.


Subject(s)
Hypertension , Pre-Eclampsia , Female , Humans , Pregnancy , Biomarkers , Placenta , Placenta Growth Factor , Pre-Eclampsia/diagnosis , Vascular Endothelial Growth Factor Receptor-1
7.
J Biol Inorg Chem ; 27(4-5): 393-403, 2022 08.
Article in English | MEDLINE | ID: mdl-35488931

ABSTRACT

Metal ion dysregulation has been implicated in a number of diseases from neurodegeneration to cancer. While defective metal ion transport mechanisms are known to cause specific diseases of genetic origin, the role of metal dysregulation in many diseases has yet to be elucidated due to the complicated function (both good and bad!) of metal ions in the body. A breakdown in metal ion speciation can manifest in several ways from increased reactive oxygen species (ROS) generation to an increase in protein misfolding and aggregation. In this review, we will discuss the role of Zn in the proper function of the p53 protein in cancer. The p53 protein plays a critical role in the prevention of genome mutations via initiation of apoptosis, DNA repair, cell cycle arrest, anti-angiogenesis, and senescence pathways to avoid propagation of damaged cells. p53 is the most frequently mutated protein in cancer and almost all cancers exhibit malfunction along the p53 pathway. Thus, there has been considerable effort dedicated to restoring normal p53 expression and activity to mutant p53. This includes understanding the relative populations of the Zn-bound and Zn-free p53 in wild-type and mutant forms, and the development of metallochaperones to re-populate the Zn binding site to restore mutant p53 activity. Parallels will be made to the development of multifunctional metal binding agents for modulating the aggregation of the amyloid-beta peptide in Alzheimer's Disease (AD).


Subject(s)
Neoplasms , Tumor Suppressor Protein p53 , Chemistry, Bioinorganic , Humans , Metallochaperones/metabolism , Metals/metabolism , Mutation , Neoplasms/genetics , Neoplasms/metabolism , Tumor Suppressor Protein p53/chemistry , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Zinc/chemistry
8.
J Appl Lab Med ; 7(1): 57-65, 2022 01 05.
Article in English | MEDLINE | ID: mdl-34342347

ABSTRACT

BACKGROUND: In North America, both messenger RNA (mRNA) vaccines, Pfizer-BioNTech BNT162b2, and Moderna mRNA-1273, each utilizing a 2-dose regimen, have started to be administered to individuals. METHODS: We evaluated the quantitative serologic antibody response following administration of either a single dose or both doses of an mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in a cohort of 98 participants (88 healthcare workers [HCW] and 10 solid organ transplant [SOT] recipients). Antibody levels were compared across 3 immunoassays: Elecsys Anti-SARS-CoV-2 S (Roche Diagnostics), SARS-CoV-2 TrimericS IgG (DiaSorin), and SARS-CoV-2 IgG II Quant (Abbott). RESULTS: Among HCW, sensitivity ranged from 100% (Roche), 99% (Abbott) and 98% (DiaSorin). The SARS-CoV-2 IgG II Quant and SARS-CoV-2 TrimericS IgG assays showed good agreement with a Pearson correlation coefficient of R = 0.95. Pearson correlation coefficients of R = 0.82 and 0.83 were obtained for Elecsys Anti-SARS-CoV-2 S vs SARS-CoV-2 TrimericS IgG and SARS-CoV-2 IgG II Quant vs Elecsys Anti-SARS-CoV-2 S, respectively. Significant differences in antibody levels between HCW and SOT recipients were observed. A decrease in antibody levels from time of vaccine administration to blood draw was evident. Among those with a second dose, an increase in antibody levels with increased time between administration of the first and second dose was observed. CONCLUSIONS: The absolute values generated from each of the assay platforms are not interchangeable. Antibody levels differed with increased time between vaccine administration and with increased time between administration of the first and second dose. Further, significant differences in antibody levels between HCW and SOT recipients were observed.


Subject(s)
COVID-19 , SARS-CoV-2 , 2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19 Vaccines , Humans , Immunoassay
9.
Chem Soc Rev ; 49(19): 6995-7014, 2020 Oct 05.
Article in English | MEDLINE | ID: mdl-32869798

ABSTRACT

Referred to as the "guardian of the genome", p53 is the most frequently mutated protein in cancer and almost all cancers exhibit malfunction along the p53 pathway. As an overexpressed and tumour-specific target, the past two decades have seen considerable dedication to the development of small molecules that aim to restore wild-type function in mutant p53. In this review we collect and communicate the chemical principles involved in small molecule drug design for misfolded proteins in anticancer therapy. While this approach has met with significant challenges including off-target mechanisms that induce cytotoxicity independent of p53 status, major technological advancements in gene sequencing capability and a shift towards personalized medicine holds significant promise for p53 reactivating compounds and could have widespread benefits for the field of cancer therapy.


Subject(s)
Antineoplastic Agents/therapeutic use , Neoplasms/drug therapy , Small Molecule Libraries/therapeutic use , Tumor Suppressor Protein p53/drug effects , Antineoplastic Agents/pharmacology , Humans , Molecular Targeted Therapy , Mutation , Small Molecule Libraries/pharmacology , Tumor Suppressor Protein p53/genetics
10.
Cell ; 182(4): 1027-1043.e17, 2020 08 20.
Article in English | MEDLINE | ID: mdl-32822567

ABSTRACT

Cell-surface protein-protein interactions (PPIs) mediate cell-cell communication, recognition, and responses. We executed an interactome screen of 564 human cell-surface and secreted proteins, most of which are immunoglobulin superfamily (IgSF) proteins, using a high-throughput, automated ELISA-based screening platform employing a pooled-protein strategy to test all 318,096 PPI combinations. Screen results, augmented by phylogenetic homology analysis, revealed ∼380 previously unreported PPIs. We validated a subset using surface plasmon resonance and cell binding assays. Observed PPIs reveal a large and complex network of interactions both within and across biological systems. We identified new PPIs for receptors with well-characterized ligands and binding partners for "orphan" receptors. New PPIs include proteins expressed on multiple cell types and involved in diverse processes including immune and nervous system development and function, differentiation/proliferation, metabolism, vascularization, and reproduction. These PPIs provide a resource for further biological investigation into their functional relevance and may offer new therapeutic drug targets.


Subject(s)
Ligands , Protein Interaction Maps/physiology , Receptors, Cell Surface/metabolism , DCC Receptor/chemistry , DCC Receptor/metabolism , Humans , Phylogeny , Receptor-Like Protein Tyrosine Phosphatases, Class 2/chemistry , Receptor-Like Protein Tyrosine Phosphatases, Class 2/metabolism , Receptors, Cell Surface/chemistry , Receptors, Cell Surface/classification , Receptors, Interleukin-1/chemistry , Receptors, Interleukin-1/metabolism , Signaling Lymphocytic Activation Molecule Family/chemistry , Signaling Lymphocytic Activation Molecule Family/metabolism , Surface Plasmon Resonance
11.
West J Nurs Res ; 42(11): 948-962, 2020 11.
Article in English | MEDLINE | ID: mdl-32075541

ABSTRACT

Multiple chronic conditions (MCC) are becoming increasingly common and self-management (SM) interventions to address MCC are emerging. Prior reviews have broadly examined SM interventions in MCC; however, interventional components were not thoroughly described. Components of SM interventions that have been delivered to individuals with MCC were identified. A review of CINAHL, Cochrane, PubMed, PsycINFO, Scopus, and Embase was completed. This search yielded 13,994 potential studies; 31 studies among those 13,994 studies met inclusion for analysis. The literature is multidisciplinary and describes a wide variety of interventional strategies implementing various combinations of components. A descriptive analysis of the studies' components, application of the components, delivery methods, and primary outcomes demonstrated clear variations between programs. The most common components noted in the 31 studies were education, action planning/goal setting, self-monitoring, and social/peer support. The variation in SM programs limits conclusive evidence for which components are recommended to improve self-management in individuals with MCC.


Subject(s)
Chronic Disease/therapy , Comorbidity , Goals , Patient Education as Topic , Self-Management , Humans , Randomized Controlled Trials as Topic , Social Support
12.
Methods Mol Biol ; 2025: 93-142, 2019.
Article in English | MEDLINE | ID: mdl-31267450

ABSTRACT

Recombinant protein expression and purification is an essential component of biomedical research and drug discovery. Advances in automation and laboratory robotics have enabled the development of highly parallel and rapid processes for cell culture and protein expression, purification, and analysis. Human embryonic kidney (HEK) cells and Chinese hamster ovary (CHO) cells have emerged as the standard host cell workhorses for producing recombinant secreted mammalian proteins by using both transient and stable production strategies. In this chapter we describe a fully automated custom platform, Protein Expression and Purification Platform (PEPP), used for transient protein production from HEK cells and stable protein production from CHO cells. Central to PEPP operation is a suite of custom robotic and instrumentation platforms designed and built at GNF, custom cell culture ware, and custom scheduling software referred to as Runtime. The PEPP platform enables cost-effective, facile, consistent production of proteins at quantities and quality useful for early stage drug discovery tasks such as screening, bioassays, protein engineering, and analytics.


Subject(s)
Recombinant Proteins/metabolism , Animals , CHO Cells , Cricetulus , Drug Delivery Systems , HEK293 Cells , Humans , Protein Engineering , Recombinant Proteins/genetics
13.
Chem Commun (Camb) ; 55(43): 6082-6085, 2019 May 28.
Article in English | MEDLINE | ID: mdl-31066383

ABSTRACT

The design and synthesis of a supramolecular square was achieved by coordination-driven assembly of redox-active nickel(ii) salen linkers and (ethylenediamine)palladium(ii) nodes. The tetrameric geometry of the supramolecular structure was confirmed via MS, NMR, and electrochemical experiments. While oxidation of the monomeric metalloligand Schiff-base affords a Ni(iii) species, oxidation of the coordination-driven assembly results in ligand radical formation.

14.
Forensic Sci Res ; 4(1): 51-59, 2019.
Article in English | MEDLINE | ID: mdl-30915417

ABSTRACT

The generation of a DNA profile from skeletal remains is an important part of the identification process in both mass disaster and unidentified person cases. Since bones and teeth are often the only biological materials remaining after exposure to environmental conditions, intense heat, certain traumatic events and in cases where a significant amount of time has passed since the death of the individual, the ability to purify large quantities of informative DNA from these hard tissues would be beneficial. Since sampling the hard tissues for genetic analysis is a destructive process, it is important to understand those environmental and intrinsic factors that contribute to DNA preservation. This will serve as a brief introduction to these topics, since skeletal sampling strategies and molecular taphonomy have been discussed in depth elsewhere. Additionally advances in skeletal DNA extraction and analysis will be discussed. Currently there is great variation in the DNA isolation methods used by laboratories to purify DNA from the hard tissues; however, a standardized set of short tandem repeat (STR) loci is analyzed by many US laboratories to allow for comparisons across samples and jurisdictions. Recent advances have allowed for the generation of DNA profiles from smaller quantities of template DNA and have expanded the number of loci analyzed for greater discriminatory power and predictions regarding the geographic ancestry and phenotype of the individual. Finally, utilizing databases and expanding the number of comparison samples will be discussed in light of their role in the identification process.

15.
Chem Sci ; 10(46): 10802-10814, 2019 Dec 14.
Article in English | MEDLINE | ID: mdl-32055386

ABSTRACT

Protein misfolding and aggregation contributes to the development of a wide range of diseases. In cancer, over 50% of diagnoses are attributed to p53 malfunction due to missense mutations, many of which result in protein misfolding and accelerated aggregation. p53 mutations also frequently result in alteration or loss of zinc at the DNA-binding site, which increases aggregation via nucleation with zinc-bound p53. Herein, we designed two novel bifunctional ligands, LI and LH , to modulate mutant p53 aggregation and restore zinc binding using a metallochaperone approach. Interestingly, only the incorporation of iodine function in LI resulted in modulation of mutant p53 aggregation, both in recombinant and cellular environments. Native mass spectrometry shows a protein-ligand interaction for LI , as opposed to LH , which is hypothesized to lead to the distinct difference in the p53 aggregation profile for the two ligands. Incorporation of a di-2-picolylamine binding unit into the ligand design provided efficient intracellular zinc uptake, resulting in metallochaperone capability for both LI and LH . The ability of LI to reduce mutant p53 aggregation results in increased restoration of p53 transcriptional function and mediates both caspase-dependent and -independent cell death pathways. We further demonstrate that LI exhibits minimal toxicity in non-cancerous organoids, and that it is well tolerated in mice. These results demonstrate that iodination of our ligand framework restores p53 function by interacting with and inhibiting mutant p53 aggregation and highlights LI as a suitable candidate for comprehensive in vivo anticancer preclinical evaluations.

16.
Chemistry ; 24(67): 17734-17742, 2018 Dec 03.
Article in English | MEDLINE | ID: mdl-30230059

ABSTRACT

The p53 protein plays a major role in cancer prevention, and over 50 % of cancer diagnoses can be attributed to p53 malfunction. The common p53 mutation Y220C causes local protein unfolding, aggregation, and can result in a loss of Zn in the DNA-binding domain. Structural analysis has shown that this mutant creates a surface site that can be stabilized using small molecules, and herein a multifunctional approach to restore function to p53-Y220C is reported. A series of compounds has been designed that contain iodinated phenols aimed for interaction and stabilization of the p53-Y220C surface cavity, and Zn-binding fragments for metallochaperone activity. Their Zn-binding affinity was characterized using spectroscopic methods and demonstrate the ability of compounds L4 and L5 to increase intracellular levels of Zn2+ in a p53-Y220C-mutant cell line. The in vitro cytotoxicity of our compounds was initially screened by the National Cancer Institute (NCI-60), followed by testing in three stomach cancer cell lines with varying p53 status', including AGS (WTp53), MKN1 (V143A), and NUGC3 (Y220C). Our most promising ligand, L5, is nearly 3-fold more cytotoxic than cisplatin in a large number of cell lines. The impressive cytotoxicity of L5 is further maintained in a NUGC3 3D spheroid model. L5 also induces Y220C-specific apoptosis in a cleaved caspase-3 assay, reduces levels of unfolded mutant p53, and recovers p53 transcriptional function in the NUGC3 cell line. These results show that these multifunctional scaffolds have the potential to restore wild-type function in mutant p53-Y220C.


Subject(s)
Coordination Complexes/metabolism , Tumor Suppressor Protein p53/metabolism , Binding Sites , Cell Line, Tumor , Cell Survival/drug effects , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Drug Design , Humans , Ligands , Microscopy, Fluorescence , Molecular Conformation , Molecular Docking Simulation , Neoplasms/metabolism , Neoplasms/pathology , Polymorphism, Single Nucleotide , Protein Structure, Tertiary , Tumor Suppressor Protein p53/chemistry , Tumor Suppressor Protein p53/genetics , Zinc/chemistry , Zinc/metabolism
17.
Inorg Chem ; 57(14): 8211-8217, 2018 Jul 16.
Article in English | MEDLINE | ID: mdl-29939728

ABSTRACT

Conversion of biological molecules into fuels or other useful chemicals is an ongoing chemical challenge. One class of enzymes that has received attention for such applications is aldehyde deformylating oxygenase (ADO) enzymes. These enzymes convert aliphatic aldehydes to the alkanes and formate. In this work, we prepared and investigated ADO enzymes modified with RuII(tris-diimine) photosensitizers as a starting point for probing intramolecular electron transfer events. Three variants were prepared, with RuII-modification at the wild type (WT) residue C70, at the R62C site in one mutant ADO, and at both C62 and C70 in a second mutant ADO protein. The single-site modification of WT ADO at C70 using a cysteine-reactive label is an important observation and opens a way forward for new studies of electron flow, mechanism, and redox catalysis in ADO. These Ru-ADO constructs can perform the ADO catalytic cycle in the presence of light and a sacrificial reductant. In this work, the Ru photosensitizer serves as a tethered, artificial reductase that promotes turnover of aldehyde substrates with different carbon chain lengths. Peroxide side products were detected for shorter chain aldehydes, concomitant with less productive turnover. Analysis using semiclassical electron transfer theory supports proposals for hopping pathway for electron flow in WT ADO and in our new Ru-ADO proteins.


Subject(s)
Carbon-Carbon Lyases/chemistry , Coordination Complexes/chemistry , Electrons , Photosensitizing Agents/chemistry , Ruthenium/chemistry , Carbon-Carbon Lyases/genetics , Carbon-Carbon Lyases/radiation effects , Catalysis , Coordination Complexes/radiation effects , Ligands , Light , Mutation , Oxidation-Reduction , Photosensitizing Agents/radiation effects , Synechococcus/enzymology
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