Effect of bet missense mutations on bromodomain function, inhibitor binding and stability

Lysine acetylation is an important epigenetic mark regulating gene transcription and chromatin structure. Acetylated lysine residues are specifically recognized by bromodomains, small protein interaction modules that read these modification in a sequence and acetylation dependent way regulating the recruitment of transcriptional regulators and chromatin remodelling enzymes to acetylated sites in chromatin. Recent studies revealed that bromodomains are highly druggable protein interaction domains resulting in the development of a large number of bromodomain inhibitors. BET bromodomain inhibitors received a lot of attention in the oncology field resulting in the rapid translation of early BET bromodomain inhibitors into clinical studies. Here we investigated the effects of mutations present as polymorphism or found in cancer on BET bromodomain function and stability and the influence of these mutants on inhibitor binding. We found that most BET missense mutations localize to peripheral residues in the two terminal helices. Crystal structures showed that the three dimensional structure is not compromised by these mutations but mutations located in close proximity to the acetyl-lysine binding site modulate acetyl-lysine and inhibitor binding. Most mutations affect significantly protein stability and tertiary structure in solution, suggesting new interactions and an alternative network of protein-protein interconnection as a consequence of single amino acid substitution. To our knowledge this is the first report studying the effect of mutations on bromodomain function and inhibitor binding

\u3cem\u3eM. ruber\u3c/em\u3e Mrub_3013 is Orthologous to \u3cem\u3eE. coli\u3c/em\u3e b2755

This project is part of the Meiothermus ruber genome analysis project, which uses a collection of online bioinformatics tools to predict gene function. We investigated the biological function of gene Mrub_3013, which we hypothesize is orthologous to b2755 in E. coli K12 MG1655 (a.k.a. Cas1). We investigated the biological function of a gene with the M. ruber locus tag of Mrub_3013, which we hypothesize is a component of the CRISPR-Cas prokaryotic defense system in M. ruber. We predict that Mrub_3013 (DNA coordinates 3,053,978-3,054,940) encodes the protein Cas1 which as part of the CRISPR-Cas system, selects and cuts the foreign DNA to make the spacer using the Cas1-Cas2 complex to restrict the size for recognition of an appropriate protospacer. Our hypothesis is supported by identical hits for Mrub_3013 and b2755 to the KEGG, TIGRfam, CDD and PDB databases, as well as a low E-value for a pairwise NCBI BLAST comparison. Both protein products are predicted to be localized to the cytoplasm due to TMHMM probabilities, PRED-TMBB probabilities, and PSORT-B data scores

Women at a Glance

Writings and art about female condoms, parenting, purity balls, marriage, abusive relationships, and rape culture.https://digitalcommons.chapman.edu/feminist_zines/1027/thumbnail.jp

Unveiling the folding mechanism of the bromodomains

Bromodomains (BRDs) are small protein domains often present in large multidomain proteins involved in transcriptional regulation in eukaryotic cells. They currently represent valuable targets for the development of inhibitors of aberrant transcriptional processes in a variety of human diseases. Here we report urea-induced equilibrium unfolding experiments monitored by circular dichroism (CD) and fluorescence on two structurally similar BRDs: BRD2(2) and BRD4(1), showing that BRD4(1) is more stable than BRD2(2). Moreover, we report a description of their kinetic folding mechanism, as obtained by careful analysis of stopped-flow and temperature-jump data. The presence of a high energy intermediate for both proteins, suggested by the non-linear dependence of the folding rate on denaturant concentration in the millisec time regime, has been experimentally observed by temperature-jump experiments. Quantitative global analysis of all the rate constants obtained over a wide range of urea concentrations, allowed us to propose a common, three-state, folding mechanism for these two BRDs. Interestingly, the intermediate of BRD4(1) appears to be more stable and structurally native-like than that populated by BRD2(2). Our results underscore the role played by structural topology and sequence in determining and tuning the folding mechanism

Single nucleotide variants in pathological tissues: effect on protein structure and stability

Single nucleotide variants are the most frequent form of human genetic variation occurring, on average, approximately every 1200 base pairs. nsSNPs occur in the DNA coding region and lead to an amino acid change in the protein, missense mutation, that is interesting in medical biology because it may affect protein function and lead to pathogenic phenotypes. Furthermore, nsSNPs have been shown to be related to drugs sensitivity suggesting new therapeutic personalized strategies. In most of the cases the SNPs stability has been considered to be responsible of the mutations impact on the pathological conditions or on the genetic susceptibility to diseases of the individuals. The most common cause of protein loss of function is the destabilization of its native structure and SNPs have been reported to affect protein folding and to produce changes in thermodynamic stability. Experimental studies on thermal and thermodynamic stability of some natural protein variants expressed in cancer tissues revealed a decrease in thermal stability and an increase of protein flexibility. nsSNPs may influence an individual’s susceptibility to disease -or response to drugs- through their impacts on a protein’s structure and hence cause functional changes. The future of SNP analysis greatly lies in the development of personalized medicines that can facilitate the treatment of disorders induced by genomic variations. The knowledge of SNPs will help in understanding pharmacokinetics or pharmacodynamics and how drugs act in individuals with different genetic variants. Diseases with different SNPs may become relevant pharmacogenomic targets for drug therapy

Better Student Success through Better Accessibility

This is the supplemental slide presentation that accompanied a presentation detailing accessibility services offered to students with diverse needs at Parkland College

Factors Affecting NCLEX-RN Success in an Associate Degree Nursing Program

An acute nursing shortage currently exists in the United States. It is important for nursing programs to prepare nursing students who are able to pass the NCLEX-RN. The purpose of this study was to determine whether a link exists between nursing student performance in program requirements and ultimate success or failure on the NCLEX-RN. A random sample of the nursing students at one community college who graduated in the calendar years of 2017 and 2018 were the population for this study. This comparative study examined data in existence to determine if there were academic factors relating to failure on NCLEX-RN. Chi-square was used to determine a relationship and phi-coefficient was used to determine the strength of that relationship between dependent and independent variables. A weak to moderate association was found between failure on NCLEX-RN and the independent variables: low score on the science portion of the TEAS test, need to repeat the first medical-surgical nursing course, and less than 850 on HESI exit. Future research should focus on the connection between mathematics scores and success in the nursing program and NCLEX-RN. Keywords: Nursing education, NCLEX-RN pass rates, nursing education readiness, healthcare education, student success. DOI: 10.7176/JEP/12-30-01 Publication date:October 31st 202