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DNA polymerase β (Pol β) fills single nucleotide gaps during base excision repair. Deficiencies in Pol β can lead to increased mutagenesis and genomic instability in the cell, resulting in cancer. Our laboratory has previously shown that the I260 M somatic mutation of Pol β, which was first identified in prostate cancer, has reduced nucleotide discrimination in a sequence context-dependent manner. I260 M incorporates the incorrect G opposite A in this context more readily than WT. To identify the molecular mechanism of the reduced fidelity of I260M, we studied incorporation using single turnover kinetics and the nature and rates of conformational changes using steady-state fluorescence and Förster resonance energy transfer (FRET). Our data indicate that the I260 M mutation affects the fingers region of rat Pol β by creating a "collapsed" state in both the open (in the absence of nucleotide) and closed (prior to chemistry) states. I260 M is a temperature-sensitive mutator and binds nucleotides tighter than the WT protein, resulting in reduced fidelity compared to the WT. Additionally, we have generated a kinetic model of WT and I260 M using FRET and single turnover data, which demonstrates that I260 M precatalytic conformation changes differ compared to the WT as it is missing a precatalytic noncovalent step. Taken together, these results suggest that the collapsed state of I260 M may decrease its ability for nucleotide discrimination, illustrating the importance of the "fingers closing" conformational change for polymerase fidelity and accurate DNA synthesis.

The catalytic function of DNA polymerase β (pol β) fulfills the gap-filling requirement of the base excision DNA repair pathway by incorporating a single nucleotide into a gapped DNA substrate resulting from the removal of damaged DNA bases. Most importantly, pol β can select the correct nucleotide from a pool of similarly structured nucleotides to incorporate into DNA in order to prevent the accumulation of mutations in the genome. Pol β is likely to employ various mechanisms for substrate selection. Here, we use dCTP analogues that have been modified at the β,γ-bridging group of the triphosphate moiety to monitor the effect of leaving group basicity of the incoming nucleotide on precatalytic conformational changes, which are important for catalysis and selectivity. It has been previously shown that there is a linear free energy relationship between leaving group p K a and the chemical transition state. Our results indicate that there is a similar relationship with the rate of a precatalytic conformational change, specifically, the closing of the fingers subdomain of pol β. In addition, by utilizing analogue β,γ-CHX stereoisomers, we identified that the orientation of the β,γ-bridging group relative to R183 is important for the rate of fingers closing, which directly influences chemistry.

Despite demonstrated efficacy of vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease-2019 (COVID-19), widespread hesitancy to vaccination persists. Improved knowledge regarding frequency, severity, and duration of vaccine-associated symptoms may help reduce hesitancy. In this prospective observational study, we studied 1032 healthcare workers who received both doses of the Pfizer-BioNTech SARS-CoV-2 mRNA vaccine and completed post-vaccine symptom surveys both after dose 1 and after dose 2. We defined appreciable post-vaccine symptoms as those of at least moderate severity and lasting at least 2 days. We found that symptoms were more frequent following the second vaccine dose than the first (74% vs. 60%, P < 0.001), with >80% of all symptoms resolving within 2 days. The most common symptom was injection site pain, followed by fatigue and malaise. Overall, 20% of participants experienced appreciable symptoms after dose 1 and 30% after dose 2. In multivariable analyses, female sex was associated with greater odds of appreciable symptoms after both dose 1 (OR, 95% CI 1.73, 1.19-2.51) and dose 2 (1.76, 1.28-2.42). Prior COVID-19 was also associated with appreciable symptoms following dose 1, while younger age and history of hypertension were associated with appreciable symptoms after dose 2. We conclude that most post-vaccine symptoms are reportedly mild and last <2 days. Appreciable post-vaccine symptoms are associated with female sex, prior COVID-19, younger age, and hypertension. This information can aid clinicians in advising patients on the safety and expected symptomatology associated with vaccination., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

We compared the prevalence of exposure to violence across different types of alcohol consumed and the association between the type of alcohol consumed and exposure to violence. A cross-sectional analysis of data collected from a sample of 295 Emergency Department (ED) patients identified as having an alcohol problem. Outcome measure include exposure to violence, and the main study predictor was "type of alcoholic drink" including: malt liquor beer (MLB), regular beer, wine cooler, wine, fortified wine or hard liquor. Using logistic regression analysis, ED patients who drank MLB in combination with other types of alcohol increased their odds of being both threatened and physically attacked by 8.5 compared to ED patients who drank other types of alcohol. Being female increased the odds of being both threatened and physically attacked by 2.5 and using illicit drugs increased the odds by 3.8. Analysis of covariance and estimated marginal means revealed that ED patients who only drank MLB had a higher exposure to violence compared to non-MLB drinkers, and that female illicit drug users who drank MLB in combination with other types of alcohol had the highest exposure to violence. MLB was identified as a predictor of the amount of exposure to violence and in particular, that the use of malt liquor beer in combination with other types of alcohol increased the risk of being both threatened and physically attacked. Implications for ED and community interventions are suggested.

Using standard immunohistochemical procedures, we investigated the changes in the expression of ionotropic glutamate receptor (GluR) subunits, GluRl, GluR5/6/7, and NMDAR1, in the subthalamic nucleus of developing rats. The general sequence of development for each subunit was the same. At early postnatal ages, there was dense neuropil staining and cellular clustering which progressed to decreased neuropil staining and an even distribution of conspicuous cells in the later postnatal ages and in the adult. GluR5/6/7 displayed the earliest maturation, while GluR1 exhibited the slowest maturation. These morphological changes suggest a different time course for the functionality of GluR subtypes in the developing subthalamic nucleus. Correlative electrophysiological studies demonstrated functional GluRs as early as 16 days of age. All neurons tested displayed robust responses to kainate and N-methyl-D-aspartate, and these responses were modulated by dopamine., (Copyright 2003 S. Karger AG, Basel)