Differential Sources of Resistance from Lactuca serriola Against Three Races of Xanthomonas hortorum pathovar vitians (Brown, 1918) Morinière et al. 2020 Causing Bacterial Leaf Spot of Lettuce.

Bacterial leaf spot (BLS) of lettuce (Lactuca sativa L.) is caused by the bacterium Xanthomonas hortorum pv. vitians which is hypothesized to have at least three races of the pathogen present in North America as defined by their differential resistance phenotypes in lettuce cultivars/accessions. Though resistance to X. hortorum pv. vitians race 1 has been identified in cultivated lettuce, numerous other X. hortorum pv. vitians strains cause disease on cultivars carrying this resistance locus. Thus far, resistance to these 'additional' X. hortorum pv. vitians strains has not been adequately described in L. sativa or in any other wild Lactuca species sexually compatible with cultivated lettuce. We have performed an extensive screening of approximately 500 Lactuca accessions from L. sativa, L. serriola, L. saligna, L. virosa, L. aculeata, L. altaica, and L. perennis species to identify accessions resistant to these additional X. hortorum pv. vitians races. Following the initial screenings, greenhouse tests confirmed that X. hortorum pv. vitians race 2 and race 3 could be defined using Lactuca sativa accessions. Race 2 strain BS3217 had an incompatible response (hypersensitive response) on ten Lactuca serriola accessions including PI491114 and PI491108, while race 1 (BS0347) and race 3 (BS2861) strains of X. hortorum pv. vitians showed a compatible response (disease) on these genotypes. L. serriola accession ARM09-161 (and selections derived from it) was the only genotype resistant to the race 3 strain BS2861. L. serriola accessions identified in this study to be resistant to race 2 and race 3 of X. hortorum pv. vitians, together with race 1 resistant cultivars, can be used for pyramiding resistance loci against the three races of the BLS-causing pathogen.

Structural Insights into Alterations in the Substrate Spectrum of Serine-ß-Lactamase OXA-10 from Pseudomonas aeruginosa by Single Amino Acid Substitutions.

The extensive use of ß-lactam antibiotics has led to significant resistance, primarily due to hydrolysis by ß-lactamases. OXA class D ß-lactamases can hydrolyze a wide range of ß-lactam antibiotics, rendering many treatments ineffective. We investigated the effects of single amino acid substitutions in OXA-10 on its substrate spectrum. Broad-spectrum variants with point mutations were searched and biochemically verified. Three key residues, G157D, A124T, and N73S, were confirmed in the variants, and their crystal structures were determined. Based on an enzyme kinetics study, the hydrolytic activity against broad-spectrum cephalosporins, particularly ceftazidime, was significantly enhanced by the G157D mutation in loop 2. The A124T or N73S mutation close to loop 2 also resulted in higher ceftazidime activity. All structures of variants with point mutations in loop 2 or nearby exhibited increased loop 2 flexibility, which facilitated the binding of ceftazidime. These results highlight the effect of a single amino acid substitution in OXA-10 on broad-spectrum drug resistance. Structure-activity relationship studies will help us understand the drug resistance spectrum of ß-lactamases, enhance the effectiveness of existing ß-lactam antibiotics, and develop new drugs.

Molecular and Cellular Mechanisms of Motor Circuit Development.

Motor circuits represent the main output of the central nervous system and produce dynamic behaviors ranging from relatively simple rhythmic activities like swimming in fish and breathing in mammals to highly sophisticated dexterous movements in humans. Despite decades of research, the development and function of motor circuits remain poorly understood. Breakthroughs in the field recently provided new tools and tractable model systems that set the stage to discover the molecular mechanisms and circuit logic underlying motor control. Here, we describe recent advances from both vertebrate (mouse, frog) and invertebrate (nematode, fruit fly) systems on cellular and molecular mechanisms that enable motor circuits to develop and function and highlight conserved and divergent mechanisms necessary for motor circuit development.

Transcriptomic cell-type specificity of local cortical circuits.

Complex neocortical functions rely on networks of diverse excitatory and inhibitory neurons. While local connectivity rules between major neuronal subclasses have been established, the specificity of connections at the level of transcriptomic subtypes remains unclear. We introduce single transcriptome assisted rabies tracing (START), a method combining monosynaptic rabies tracing and single-nuclei RNA sequencing to identify transcriptomic cell types, providing inputs to defined neuron populations. We employ START to transcriptomically characterize inhibitory neurons providing monosynaptic input to 5 different layer-specific excitatory cortical neuron populations in mouse primary visual cortex (V1). At the subclass level, we observe results consistent with findings from prior studies that resolve neuronal subclasses using antibody staining, transgenic mouse lines, and morphological reconstruction. With improved neuronal subtype granularity achieved with START, we demonstrate transcriptomic subtype specificity of inhibitory inputs to various excitatory neuron subclasses. These results establish local connectivity rules at the resolution of transcriptomic inhibitory cell types.

A single Leishmania adenylate forming enzyme of the ANL superfamily generates both acetyl- and acetoacetyl-CoA.

Leishmania, a protozoan parasite, is responsible for significant morbidity and mortality worldwide, manifesting as cutaneous, mucocutaneous, and visceral leishmaniasis. These diseases pose a substantial burden, especially in impoverished regions with limited access to effective medical treatments. Current therapies are toxic, have low efficacy, and face growing resistance. Understanding the metabolic pathways of Leishmania, particularly those differing from its host, can unveil potential therapeutic targets. In this study, we investigated the acetyl-CoA synthetase (ACS) enzyme from Leishmania infantum (LiAcs1), which, unlike many organisms, also exhibits acetoacetyl-CoA synthetase (KBC) activity. This dual functionality is unique among ANL superfamily enzymes and crucial for the parasite's reliance on leucine catabolism, energy production and sterol biosynthesis. Our biochemical characterization of LiAcs1 revealed its ability to utilize both acetate and acetoacetate substrates. Additionally, LiAcs1 displayed a distinct CoA substrate inhibition pattern, partially alleviated by acetoacetate. Structural analysis provided insights into the substrate binding flexibility of LiAcs1, highlighting a more promiscuous substrate pocket compared to other ACS or KBC-specific enzymes. Substrate mimetics elucidated its ability to accommodate both small and large AMP-ester derivatives, contributing to its dual ACS/KBC functionality. These findings not only advance our understanding of Leishmania metabolism but also present LiAcs1 as a promising drug target. The dual functionality of LiAcs1 underscores the potential for developing selective inhibitors that could disrupt critical metabolic pathways across Leishmania spp. as it appears this enzyme is highly conserved across this genus. This paves the way for developing novel effective treatments against this devastating disease.

Validation and correlation of high-sensitive troponin I and troponin T in the emergency department.

BACKGROUND: Troponin elevation is frequently observed in various scenarios in the Emergency Department (ED), yet there is a paucity of studies investigating simultaneously measured high-sensitivity cardiac troponin T (hs-cTnT) and troponin I (hs-cTnI) within a diverse cohort in a clinical setting. METHODS: All patients who underwent troponin testing at a single center were eligible for this study. Only patients with simultaneous samples with hs-cTnI (Siemens) and hs-cTnT (Roche) were included, regardless of chief complaint. RESULTS: Analysis of 1987 samples from 1134 patients showed a significant correlation between hs-cTnT and hs-cTnI (r = 0.86, p < 0.01). Of these samples, 65% exceeded the upper reference limit (URL) for hs-cTnT, and 30% for hs-cTnI with 39% who exhibited elevated hs-cTnT levels alongside normal hs-cTnI levels. The area under the curve (AUC) for acute myocardial infarction (AMI) for the index visit was 0.80 (95% CI; 0.75-0.85) for hs-cTnT and 0.87 (95% CI; 0.83-0.91) for hs-cTnI. Sensitivity and specificity were 91% and 39% for hs-cTnT, and 80% and 80% for hs-cTnI. Positive predictive value (PPV) and negative predictive value (NPV) was 9.3% and 98.5% for hs-cTnT respectively, corresponding for hs-cTnI was 21.3% and 98.3% respectively. Hazard ratios for 1-year mortality were 1.52 (95% CI; 1.40-1.66) for hs-cTnT and 1.26 (95% CI; 1.18-1.34) for hs-cTnI. CONCLUSION: Elevated troponins above the URL were very common in this diverse cohort, particularly for hs-cTnT, which was twice as frequent compared to hs-cTnI, resulting in low specificity and PPV for AMI.

Enumerating genotypic diversity and host specificity of Giardia in wild rodents around a New York watershed.

Giardia is a genus of flagellated protozoans that parasitize the gastrointestinal tract of humans and wildlife worldwide. While G. duodenalis is well-studied due to its potential to cause outbreaks of diarrheal illness in humans, other Giardia species from wildlife have been largely understudied. This study examines the occurrence, host specificity, and genotypic diversity of Giardia in wild rodents living within the New York City water supply watershed. A novel nested PCR assay targeting the 18S ssu-rDNA gene is introduced, which captures nearly the entire gene for improved species-level determination versus existing molecular typing methods. Molecular characterization of 55 Giardia specimens reveals at least seven novel lineages. Phylogenetic analysis indicates a close relationship between the newly characterized Giardia lineages and rodent hosts, suggesting rodents as important reservoirs of Giardia and its close relatives. These findings provide insights into the diversity of Giardia species and their public health potential in localities with human-wildlife interaction and further emphasizes the need for continued efforts to improve the molecular tools used to study microbial eukaryotes, especially those with zoonotic potential.

Training Model for Extended Career Athletes: A Narrative Review.

CONTEXT: Today's elite and professional sports tend to feature older, more seasoned athletes, who have longer sporting careers. As advancing age can potentially limit peak performance, balancing training load is necessary to maintain an optimal state of performance and extend their sports career. OBJECTIVE: To describe an appropriate training model for extended career athletes. DATA SOURCES: Medline (PubMed), SPORTDiscus, ScienceDirect, Web of Science, and Google Scholar. STUDY SELECTION: A search of the literature between January 1, 2015 and November 22, 2023 was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. STUDY DESIGN: Narrative review. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Data were extracted from studies related to the management of training and performance of athletes with extended and long careers. RESULTS: A total of 21 articles related to extended careers were found. Key themes from these papers included: expertise, biological maturation, and specificity; epidemiology and health; athlete monitoring; strength training; load management and detraining; success management. CONCLUSION: A training model for extended career athletes should balance the deleterious effects of age with the athletes' knowledge of, and expertise within, the sport. Designing specific training that accommodates previous injuries, training load intolerances, and caters for quality of life after retirement should be key considerations. Load management strategies for athletes with extended careers should include strength training adaptations to minimize pain, load-response monitoring, a broad range of movement, recovery and intensity activities, and the avoidance of large training load peaks and periods of inactivity.

Bioinformatics-aided function exploration of GH29 fucosidases from human gut Parabacteroides.

Gut microbes produce α-l-fucosidases critical for utilizing human milk oligosaccharides, mucosal and dietary glycans. Although gut Parabacteroides have garnered attention for their impact on host health and disease, their CAZymes remain poorly studied. CAZome analysis of eleven gut Parabacteroides type strains revealed their capacity to degrade mucin O-glycans. Their abundance of GH29 fucosidases caught our attention, and we predicted the functional profiles of 46 GH29 fucosidases using in silico approaches. Our findings showed diverse linkages specificities and species-specific distributions, with over half of GH29 enzymes functioning as α1,3/4 fucosidases, essential for acting on Lewis antigen epitopes of mucin O-glycans. We further enzymatically validated 4 novel GH29 sequences from poorly characterized groups. PgoldGH29A (cluster37 GH29BERT, GH29:75.1 CUPP) does not act on tested natural substrates. PgoldGH29B (cluster1 GH29BERT, GH29:84.1 CUPP) functions as a strict α1,3/4 fucosidase. PgoldGH29C (cluster14 GH29BERT, GH29:29.1 CUPP) displays unprecedented substrate specificity for α1,2/3/4 disaccharides. PgoldGH29D (cluster4 GH29BERT, GH29:6.2 CUPP) acts on α1,2/3/4/6 linkages similar to enzymes from GH29:6.1 CUPP but prefers disaccharides over trisaccharides. These results suggest that PgoldGH29B and PgoldGH29D can contribute to mucin O-glycan degradation via their α1,3/4 and α1,2 fucosidase activity, respectively, while the natural substrates of PgoldGH29A and PgoldGH29C may be irrelevant to host-glycans. These insights enhance our understanding of the ecological niches inhabited by gut Parabacteroides and may guide similar exploration in other intriguing gut microbial species.

Corrigendum: Case report: Possible role of low-dose PEM for avoiding unneeded procedures associated with false-positive or equivocal breast MRI results.

[This corrects the article DOI: 10.3389/fonc.2024.1405404.].

Cats and dogs as hosts of Blastocystis - What is the evidence?

Blastocystis is one of the most common intestinal parasites observed in human and non-human hosts. Recent meta-analyses have indicated a potential role for pets such as dogs and cats as reservoir hosts of Blastocystis, but the data underpinning this hypothesis are of mixed quality. Reviewing data for 45,894 samples tested for Blastocystis by DNA-based methods and 11,908 subtype observations, a model was developed for calculating indices that could be used for evaluating individual species as natural hosts of Blastocystis, based on weighted products of positivity rates and subtype distributions. Data from cats and dogs were analysed, using other well-sampled hosts (pig, cattle, sheep, goat, and human) as references. Data from cats and dogs meeting the inclusion criteria were entered into the model. The overall positivity rates for pigs, cattle, sheep, goats, humans, dogs, and cats were 40 %, 40 %, 35 %, 28 %, 25 %, 6 %, and 5 %, respectively, with statistically significant lower positivity rates in cats and dogs (p < 0.0001). Indices indicating Blastocystis specificity to host ranged between 0.16 (humans) and 0.49 (cattle) for the reference hosts, whereas indices for cats and dogs were only 0.01 and 0.02, respectively. Finally, indices for ST specificity to host were higher for reference hosts (range, 0.66-0.93) than for cats (0.62) and dogs (0.56). Taken together, the analyses indicate that cats and dogs are not natural or reservoir hosts of Blastocystis and that the sporadic subtype pattern observed in these hosts might indicate exposure to Blastocystis through contaminated water/feed, including Blastocystis colonizing prey animals.

Evaluation of the specificity of the 2023 European Society of Cardiology classification for infective endocarditis.

BACKGROUND: The 2023 Duke-ISCVID and 2023 ESC classifications have recently issued independent diagnostic criteria for infective endocarditis (IE), updating the 2015 ESC criteria. OBJECTIVES: The specificity of the 2023 ESC criteria should be evaluated and compared to the two other classifications in IE suspected patients. METHODS: We retrospectively collected the characteristics of patients hospitalised in Bichat University Hospital, in 2021, who had been evaluated for suspicion of IE, and in whom IE diagnosis was finally rejected. All were classified by 2015 ESC, 2023 Duke-ISCVID, and 2023 ESC. RESULTS: In total 130 patients were analysed. Mean age was 62 years, 64.6% were male, 30.0% had prosthetic cardiac valve or valve repair, 16.2% had cardiac implanted electronic device, and 23.1% other cardiac conditions. Overall, 2, 5 and 5 patients were falsely classified as definite IE with the 2015 ESC, 2023 Duke-ISCVID and 2023 ESC criteria, respectively. The corresponding specificities were 99% (95% CI [94%; 100%], 96% (95% CI [91%; 99%]), and 96% (95% CI [91%; 99%]). CONCLUSION: The 2023 ESC and the 2023 Duke-ISCVID criteria are highly specific, although slightly less than the 2015 ESC criteria, for ruling out the diagnosis of definite IE.HIGHLIGHTS2023 Duke-ISCVID and 2023 ESC criteria are recently issued diagnostic classifications2023 ESC criteria have an excellent specificity, equivalent to the 2023 Duke-ISCVID one2023 ESC criteria and the 2023 Duke-ISCVID are less specific than the 2015 ESC criteriaSpecificities were quite similar according to the nature of the cardiac valve (native or prosthetic valve) or the duration of antibiotic therapy.

Structural basis of selective beta-carotene binding by a soluble protein.

ß-carotene (BCR) is the most abundant carotenoid, a colorant, antioxidant, and provitamin A. The extreme hydrophobicity of this hydrocarbon requires special mechanisms for distribution in aqueous media, including water-soluble carotenoproteins. However, all known carotenoproteins prefer oxygenated carotenoids and bind BCR inefficiently. Here, we present the crystal structure of the BCR-binding protein (BBP) from gregarious male locusts, which is responsible for their vivid yellow body coloration, in complex with its natural ligand, BCR. BBP forms an antiparallel tubular homodimer with α/ß-wrap folded monomers, each forming a hydrophobic 47 Å long, coaxial tunnel that opens outward and is occupied by one s-cisC6-C7, all-trans BCR molecule. In the BCR absence, BBP accepts a range of xanthophylls, with reduced efficiency depending on the position and number of oxygen atoms, but rejects lycopene. The structure captures a pigment complex with a Takeout 1 protein and inspires potential applications of BBP as a BCR solubilizer.

Modifications to the National Early Warning Score: a scoping review protocol.

INTRODUCTION: The National Early Warning Score (NEWS/2) system was developed to enable the detection and early intervention of patients at risk of clinical deterioration. It has demonstrated good accuracy in identifying imminent critical outcomes but has limitations in its applicability to various patient types and its ability to predict upcoming deterioration beyond 24 hours. Various studies have attempted to improve its predictive accuracy and clinical utility by modifying or adding variables to the standard NEWS/2 system. The purpose of this scoping review is to identify modifications to the NEWS and NEWS2 systems (eg, the inclusion of additional patient demographic, physiological or other characteristics) and how those modifications influence predictive accuracy to provide an evidence base for subsequent improvement of the system. METHODS AND ANALYSIS: The review will be structured using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews and the Population, Intervention, Comparator, Outcome, and Study frameworks. Six databases (PubMed, ScienceDirect, Embase, CINAHL, Web of Science and Cochrane Library) will be searched in April 2024 for articles published in English. Article screening and data extraction will be conducted by two independent reviewers, with any conflicts resolved by discussion. The analysis will be descriptive to provide a summary of modifications identified and their influence on the predictive accuracy of NEWS/NEWS 2. ETHICS AND DISSEMINATION: Ethical approval is not required as data will be obtained from already published sources. Findings from this study will be disseminated via publication in a peer-reviewed journal.

Performance of 5 commercial ELISA kits for the detection of antibody to bovine leukemia virus.

To prevent significant economic losses, some countries have successfully eradicated enzootic bovine leukosis (EBL), which is caused by bovine leukemia virus (BLV) infection. In Serbia, efforts to eliminate EBL commenced in the late 1990s. Recognizing the disparities in test selection among laboratories and variations in quality, we evaluated the diagnostic sensitivity and specificity of commercial ELISAs using field samples in Serbia. Using 5 commercial ELISA kits, we tested 138 cattle serum samples, submitted for confirmatory testing between 2020 and 2023, along with 100 serum samples from BLV-negative herds. We found 100% agreement of the ID Screen BLV Competition (IDvet), Svanovir BLV gp51-Ab (Svanova), and INgezim BLV Compac 2.0 (Ingenasa) ELISAs. We observed 93% agreement comparing these 3 kits to the Bovine Leukemia Virus Antibody test kit (VMRD). Agreements of 92% and 88.4% were determined between Idexx and IDvet, Svanova, and Ingenasa kits, and between Idexx and VMRD kits, respectively.

Is Cognitive Flexibility Equivalent to Shifting? Investigating Cognitive Flexibility in Multiple Domains.

In the present exploratory study we investigate whether cognitive flexibility is a unitary mechanism underlying flexible behaviours across many domains or a domain-specific capacity. The literature on cognitive flexibility is divided into several research lines that do not converge. The most prominent one considers flexibility an executive function that represents the ability to switch among rules or tasks. In other research traditions it is associated with distinct components, such as the capacity to place an item into many categories (in creativity tests) or a characteristic of different cognitive or perceptual processes (e.g., flexible language use, flexibility in mathematics, perceptual flexibility). To determine whether flexibility in different domains relies on a general shared mechanism, 221 subjects from two countries (The United States and Romania, mean age 19.52 years) were tested online with several measurements from four different domains of investigation: language, mathematics, perception, and executive functions (specifically, set shifting). All tasks required some form of cognitive flexibility. In addition, we measured math anxiety to see how this relates to mathematical flexibility. The results show very few and small significant partial correlations among the tasks. They also highlight that there is no unitary overarching "executive" factor. The most prominent common factor was speed of processing for mathematical and language response times. Shifting does not seem to be a mechanism that underlies flexibility in all the investigated domains. While we acknowledge the need for replication of this study, the data suggest that the construct of shifting does not exhaust the notion of flexibility as it arises across cognitive domains.

Multi-omics analysis of the molecular response to glucocorticoids - insights into shared genetic risk from psychiatric to medical disorders.

BACKGROUND: Alterations in the effects of glucocorticoids have been implicated in mediating some of the negative health effects associated with chronic stress, including increased risk for psychiatric disorders as well as cardiovascular and metabolic diseases. This study investigates how genetic variants influence gene expression and DNA methylation (DNAm) in response to glucocorticoid receptor (GR)-activation, and their association with disease risk. METHODS: We measured DNAm (n=199) and gene expression (n=297) in peripheral blood before and after GR-activation with dexamethasone, with matched genotype data available for all samples. A comprehensive molecular quantitative trait locus (QTL) analysis was conducted, mapping GR-response methylation (me)QTLs, GR-response expression (e)QTLs, and GR-response expression quantitative trait methylation (eQTM). A multi-level network analysis was employed to map the complex relationships between the transcriptome, epigenome, and genetic variation. RESULTS: We identified 3,772 GR-response meCpGs corresponding to 104,828 local GR-response meQTLs that did not strongly overlap with baseline meQTLs. eQTM and eQTL analyses revealed distinct genetic influences on gene expression and DNAm. Multi-level network analysis uncovered GR-response network trio QTLs, characterized by SNP-CpG-transcript combinations where meQTLs act as both eQTLs and eQTMs. GR-response trio variants were enriched in GWAS for psychiatric, respiratory, autoimmune and cardiovascular diseases and conferred a higher relative heritability per SNP than GR-response meQTL and baseline QTL SNP. CONCLUSIONS: Genetic variants modulating the molecular effects of glucocorticoids are associated with psychiatric as well as medical diseases and not uncovered in baseline QTL analyses.

Using Natural Language Processing to develop risk-tier specific suicide prediction models for Veterans Affairs patients.

Suicide is a leading cause of death. Suicide rates are particularly elevated among Department of Veterans Affairs (VA) patients. While VA has made impactful suicide prevention advances, efforts primarily target high-risk patients with documented suicide risk. This high-risk population accounts for less than 10% of VA patient suicide deaths. We previously evaluated epidemiological patterns among VA patients that had lower classified suicide risk and derived moderate- and low-risk groupings. Expanding upon VA's leading suicide prediction model, this study uses national VA data to refine high-, moderate-, and low-risk specific suicide prediction methods. We selected all VA patients who died by suicide in 2017 or 2018 (n = 4584), matching each case with five controls who remained alive during treatment year and shared suicide risk percentiles. We extracted all sample unstructured electronic health record notes, analyzed them using natural language processing, and applied machine-learning classification algorithms to develop risk-tier-specific predictive models. We calculated area under the curve (AUC) and suicide risk concentration to evaluate predictive accuracy and analyzed derived words. RESULTS: Our high-risk model (AUC = 0.621 (95% CI: 0.55-0.68)), moderate-risk (AUC = 0.669 (95% CI: 0.64-0.71)), and low-risk (AUC = 0.673 (95% CI: 0.63-0.72)) models offered significant predictive accuracy over VA's leading suicide prediction algorithm. Derived words varied considerably, the high-risk model including chronic condition service words, moderate-risk model including outpatient care, and low-risk model including acute condition care. Study suggests benefit of leveraging unstructured electronic health records and expands prediction resources for non-high-risk suicide decedents, an historically underserved population.

Structural insights into the mechanism underlying the dual cofactor specificity of glyoxylate reductase from Acetobacter aceti in the ß-hydroxyacid dehydrogenase family.

The ß-hydroxyacid dehydrogenase family exhibits diverse cofactor preferences: some enzymes favor NAD, others favor NADP, and a subset can utilize both NAD and NADPH. Glyoxylate reductase from Acetobacter aceti JCM 20276 (AacGR) exhibits a dual cofactor specificity for NADPH and NADH in its catalytic reduction of glyoxylate to glycolate. In contrast to conventional cofactor-discriminating motifs, NRX and DXX, found in NADP- and NAD-specific enzymes, respectively, AacGR has a TPS motif in the equivalent position. Here we report X-ray crystallographic analysis of AacGR in its ligand-free form, and in complexes with NADPH and NADH, revealing critical interactions: Ser41 of the TPS motif interacted with the 2'-phosphate group of NADPH, while no analogous interaction occurred with the ribose hydroxy groups of NADH. Moreover, the TPS motif resided within a characteristic ß-turn-like structure adjacent to a long flexible loop. Site-directed mutagenesis and kinetic analyses suggest that Ser41 facilitates NADPH binding, while the lack of a direct interaction of the TPS motif with NADH may allow for NADH utilization. The conformational dynamics of the TPS-containing ß-turn-like structure along with the flexible loop likely govern the dual cofactor specificity and catalytic turnover of AacGR.