منابع مشابه
Functional dynamics in the active site of the ribonuclease binase.
Binase, a member of a family of microbial guanyl-specific ribonucleases, catalyzes the endonucleotic cleavage of single-stranded RNA. It shares 82% amino acid identity with the well-studied protein barnase. We used NMR spectroscopy to study the millisecond dynamics of this small enzyme, using several methods including the measurement of residual dipolar couplings in solution. Our data show that...
متن کاملActive Site of Ribonuclease A
Ribonuclease A (RNase A; EC 3.1.27.5) was perhaps the most studied enzyme of the 20th century and is the best characterized ribonuclease. The “A” in its name refers not to its substrate specificity, but to the predominant form of the enzyme produced by the bovine pancreas. RNase A is unmodified, whereas RNase B, RNase C, and RNase D are mixtures of glycoforms. Because of its availability in lar...
متن کاملEvidence from molecular dynamics simulations of conformational preorganization in the ribonuclease H active site
Ribonuclease H1 (RNase H) enzymes are well-conserved endonucleases that are present in all domains of life and are particularly important in the life cycle of retroviruses as domains within reverse transcriptase. Despite extensive study, especially of the E. coli homolog, the interaction of the highly negatively charged active site with catalytically required magnesium ions remains poorly under...
متن کاملChemical Modifications and Kinetic Study of Ribonuclease Sa Active Site
Chemical modification experiments and kinetic measurements have been carried out to identify the active site components of guanylspecific ribonuclease Sa (E. C. 3.1.4.8.) from Streptomyces aureofaciens. Modification experiments with phenylglyoxal and diketene showed that neither arginine nor lysine residues, which could bind the negatively charged phosphate group of the substrate, belonged to t...
متن کاملExcavating an active site: the nucleobase specificity of ribonuclease A.
Ribonuclease A (RNase A) catalyzes the cleavage of RNA after pyrimidine nucleotides. When bound in the active site, the base of a pyrimidine nucleotide forms hydrogen bonds with the side chain of Thr45. Here, the role of Thr45 was probed by using the wild-type enzyme, its T45G variant, X-ray diffraction analysis, and synthetic oligonucleotides as ligands and substrates. Catalytic specificity wa...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1985
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.82.24.8458