Linked Life Data

2340284

Source:http://linkedlifedata.com/resource/pubmed/id/2340284

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-6-27
pubmed:abstractText
Crystal structures of two forms of ribonuclease A with deoxynucleosides covalently bound to respectively His 12 and His 119 have been solved. One form, T-H12-RNase, has a deoxythymidine bound to N epsilon 2 of His 12, while the other one, U-H119-RNase, has a deoxyuridine bound to N delta 1 of His 119. The two crystal forms are nearly isomorphous, with two molecules in the asymmetric unit. However, the modified ribonucleases differ both in their enzymatic activities and in the conformation of the catalytic site and of the deoxynucleoside-histidine moiety. T-H12-RNase is characterized by complete loss of enzymatic activity; in this form the deoxynucleoside completely blocks the catalytic site and forms intramolecular contacts with residues associated with both the B1 and B2 sites. U-H119-RNase retains 1% of the activity of the unmodified enzyme, and in this form His 119 adopts a different orientation, corresponding to the alternate conformation reported for this residue; the deoxynucleoside-histidine moiety points out of the active site and does not form any contacts with the rest of the protein, thus allowing partial access to the catalytic site. On the basis of these structures, we propose possible mechanisms for the reactions of bromoacetamido nucleosides with ribonuclease A.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
928-37
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Crystal structure of two covalent nucleoside derivatives of ribonuclease A.
pubmed:affiliation
BRI Basic Research Program, NCI-Frederick Cancer Research Facility, Maryland 21701.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.