Linked Life Data

12718519

Source:http://linkedlifedata.com/resource/pubmed/id/12718519

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
2003-4-29
pubmed:abstractText
Anticodon sequence mutants of Escherichia coli initiator tRNA initiate protein synthesis with codons other than AUG and amino acids other than methionine. Because the anticodon sequence is, in many cases, important for recognition of tRNAs by aminoacyl-tRNA synthetases, the mutant tRNAs are aminoacylated in vivo with different amino acids. The activity of a mutant tRNA in initiation in vivo depends on (i) the level of expression of the tRNA, (ii) the extent of aminoacylation of the tRNA, (iii) the extent of formylation of the aminoacyl-tRNA to formylaminoacyl-tRNA (fAA-tRNA), and (iv) the affinity of the fAA-tRNA for the initiation factor IF2 and the ribosome. Previously, using E. coli overproducing aminoacyl-tRNA synthetases, methionyl-tRNA formyltransferase, or IF2, we identified the steps limiting the activity in initiation of mutant tRNAs aminoacylated with glutamine and valine. Here, we have identified the steps limiting the activity of mutant tRNAs aminoacylated with isoleucine and phenylalanine. The combined results of experiments involving a variety of initiation codons (AUG, UAG, CAG, GUC, AUC, and UUC) provide support to the hypothesis that the ribosome.fAA-tRNA complex can act as an intermediate in initiation of protein synthesis. Comparison of binding affinities of various fAA-tRNAs (fMet-, fGln-, fVal-, fIle-, and fPhe-tRNAs) to IF2 using surface plasmon resonance supports the idea that IF2 can act as a carrier of fAA-tRNA to the ribosome. Other results suggest that the C1xA72 base pair mismatch, unique to eubacterial and organellar initiator tRNAs, may also be important for the binding of fAA-tRNA to IF2.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acyl-tRNA Synthetases, http://linkedlifedata.com/resource/pubmed/chemical/Anticodon, http://linkedlifedata.com/resource/pubmed/chemical/Chloramphenicol O-Acetyltransferase, http://linkedlifedata.com/resource/pubmed/chemical/Codon, http://linkedlifedata.com/resource/pubmed/chemical/Eukaryotic Initiation Factor-2, http://linkedlifedata.com/resource/pubmed/chemical/Hydroxymethyl and Formyl..., http://linkedlifedata.com/resource/pubmed/chemical/RNA, Bacterial, http://linkedlifedata.com/resource/pubmed/chemical/RNA, Transfer, http://linkedlifedata.com/resource/pubmed/chemical/RNA, Transfer, Met, http://linkedlifedata.com/resource/pubmed/chemical/methionyl-tRNA formyltransferase, http://linkedlifedata.com/resource/pubmed/chemical/tRNA, formylmethionine-
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4787-99
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Anticodon sequence mutants of Escherichia coli initiator tRNA: effects of overproduction of aminoacyl-tRNA synthetases, methionyl-tRNA formyltransferase, and initiation factor 2 on activity in initiation.
pubmed:affiliation
Department of Biology, 68-671 Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.