A true Brønsted analysis of proton transfer in an enzyme mechanism is made possible by the chemical rescue of an inactive mutant of aspartate aminotransferase, where the endogenous general base, Lys258, is replaced with Ala by site-directed mutagenesis. Catalytic activity is restored to this inactive mutant by exogenous amines. The eleven amines studied generate a Brønsted correlation with beta...

Using site-specific mutagenesis in vitro, we have constructed Escherichia coli strains that allow the detection of the inversion of an 800-bp segment in the lac region. The invertible segment is bounded by inverted repeats of either 12 or 23 bp. Inversions occurring at these inverted repeats will restore the Lac+ phenotype. Inversions can be detected at both short homologies at frequencies rang...

As an important industrial enzyme, protease is widely used in feed, food and other fields. At present, the insufficient activity obtained from microorganisms cannot meet purpose of production. In this study, Bacillus amyloliquefaciens with high production was screened animal feces by plate transparent circle method. To improve protease, atmospheric room temperature plasma (ARTP) mutagenesis fir...

The current SARS-CoV-2 pandemic underscores the importance of understanding evolution RNA genomes. While is subject to formation similar lesions as DNA, evolutionary and physiological impacts have on viral genomes are yet be characterized. Lesions that may drive can induce breaks repaired by recombination or cause base substitution mutagenesis, also known editing. Over past decade so, editing m...

Escherichia coli RNase T, an RNA-processing enzyme and a member of the DEDD exonuclease superfamily, was examined using sequence analysis and site-directed mutagenesis. Like other DEDD exonucleases, RNase T was found to contain three conserved Exo motifs that included four invariant acidic residues. Mutagenesis of these motifs revealed that they are essential for RNase T activity, indicating th...

YqjH and YqjW are Bacillus subtilis homologs of the UmuC/DinB or Y superfamily of DNA polymerases that are involved in SOS-induced mutagenesis in Escherichia coli. While the functions of YqjH and YqjW in B. subtilis are still unclear, the comparisons of protein structures demonstrate that YqjH has 36% identity to E. coli DNA polymerase IV (DinB protein), and YqjW has 26% identity to E. coli DNA...

1. Abstract 2. Introduction 3. CYP51 is an example showing the diversification process of P450 3.1. Different substrate specificity of fungal, plant, and animal CYP51s is an example of P450 diversification 3.2. Formation of C. albicans CYP51 variants through the interaction with environmental azole antifungal agents 4. Structural analysis of CYP51 4.1. Structural examination of CYP51 with site-...