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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1991-12-17
pubmed:abstractText
The complex formed between ribonuclease T1 (RNase T1) and guanosine-3',5'-bisphosphate (3',5'-pGp) crystallizes in the cubic space group I23 with alpha = 86.47 (4) A. X-ray data were collected on a four-circle diffractometer to 3.2 A resolution and the structure was determined by molecular-replacement methods [ULTIMA; Rabinovich & Shakked (1984). Acta Cryst. A40, 195-200] based on the RNase T1 coordinates taken from the complex with guanosine-2'-phosphate. Refinement converged at 16.6% for 1540 data with Fo greater than 1 sigma (Fo) with acceptable stereochemistry. The RNase T1 conformation is comparable to that in other complexes which crystallize preferentially in space group P2(1)2(1)2(1) except for side chains that interact intermolecularly. The guanine of 3',5'-pGp is bound to the recognition site in the same way as in other guanine-containing complexes except for its interaction with Glu46. The side-chain carboxylate of this amino acid does not form hydrogen bonds to N1H and N2H of guanine but is rotated so as to permit insertion of two water molecules which replace its acceptor functions. In contrast to other guanosine derivatives which are bound to RNase T1 in the syn form, 3',5'-pGp is anti. This conformation positions the two phosphate groups 'outside' the protein, with hydrogen-bonding contacts only to water molecules; the active site is filled by water. The RNase T1-3',5'-pGp complex probably has biological significance as it may represent the enzyme-product complex before dissociation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0108-7681
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
47 ( Pt 4)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
521-7
pubmed:dateRevised
2007-7-24
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
X-ray analysis of cubic crystals of the complex formed between ribonuclease T1 and guanosine-3',5'-bisphosphate.
pubmed:affiliation
Institut für Kristallographie, Freie Universität Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't