Catalytic promiscuity can facilitate evolution of enzyme functions-a multifunctional catalyst may act as a springboard for efficient functional adaptation. We test the effect of single mutations on multiple activities in two groups of promiscuous AP superfamily members to probe this hypothesis. We quantify the effect of site-saturating mutagenesis of an analogous, nucleophile-flanking residue i...

High energy irradiation to the hydrogen bonded system is important in relevance with the initial process of DNA and enzyme damages. In the present study, the effects of radiation to catalytic triad have been investigated by means of direct ab-initio molecular dynamics (AIMD) calculation. As a model of the catalytic triad, Ser-His-Glu residue, which is one of the important enzymes in the acylati...

The catalytic activation of CO single crystal surfaces is reviewed. Examples are provided which demonstrate the relevance of single crystal studies for modeling the behavior of high surface area supported catalysts. The coupling of an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh vacuum system for surface analysis allows detailed study of structure s...

It has been reported that His-119 of ribonuclease A plays a major role as an imidazolium ion acid catalyst in the cyclization/cleavage of normal dinucleotides but that it is not needed for the cyclization/cleavage of 3'-uridyl p-nitrophenyl phosphate. We see that this is also true for simple buffer catalysis, where imidazole (as in His-12 of the enzyme), but not imidazolium ion, plays a signifi...

High energy irradiation to the hydrogen bonded system is important in relevance with the initial process of DNA and enzyme damages. In the present study, the effects of radiation to catalytic triad have been investigated by means of direct ab-initio molecular dynamics (AIMD) calculation. As a model of the catalytic triad, Ser-His-Glu residue, which is one of the important enzymes in the acylati...

Mutations in the three genes encoding the heterotrimeric RNase H2 complex cause Aicardi-Goutières Syndrome (AGS). Our mouse RNase H2 structure revealed that the catalytic RNase H2A subunit interfaces mostly with the RNase H2C subunit that is intricately interwoven with the RNase H2B subunit. We mapped the positions of AGS-causing RNase H2A mutations using the mouse RNase H2 structure and propos...