Linked Life Data

2426258

Source:http://linkedlifedata.com/resource/pubmed/id/2426258

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
1986-9-17
pubmed:abstractText
We have determined several kinetic parameters for the reaction of poly(U)-programmed ribosomes with ternary complexes of elongation factor Tu, GTP, and yeast Phe-tRNA analogs with different bases substituted for uridine in position 33. These analogs test whether disruption of the hydrogen bonds normally formed by uridine 33 and steric crowding in the anticodon loop are detrimental to tRNA function on the ribosome. Single-turnover kinetic studies of the reaction of these ternary complexes with ribosomes show that these Phe-tRNA analogs decrease the apparent rate of GTP hydrolysis (kGTP) and the ratio of peptide formed to GTP hydrolyzed. Thus, the substitution of uridine 33 affects not only the selection of a ternary complex by the ribosome but also the selection of an aminoacyl-tRNA in the proofreading reaction. The effects become greater as first one, and then the other, H-bond is disrupted. Steric crowding in the anticodon loop is also important, but does not have as great an effect on the rate constants. An analysis of the elementary rate constants which comprise the rate constant, kGTP, demonstrates that the reduction in kGTP results from a decreased rate of ternary complex association with the ribosome (k1) and that there is little or no effect on the rate of GTP cleavage (k2). An analysis of the rate constants involved in proofreading shows that all the modified (tRNAs have increased rates of aminoacyl-tRNA rejection (k4) but that the rate of peptide bond formation (k3) is unaffected.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
261
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10112-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Effect of replacing uridine 33 in yeast tRNAPhe on the reaction with ribosomes.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.