Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2008-4-28
pubmed:abstractText
Representing one of the most fascinating RNA polymerases, the CCA-adding enzyme (tRNA nucleotidyltransferase) is responsible for synthesis and repair of the 3'-terminal CCA sequence in tRNA transcripts. As a consequence of this important function, this enzyme is found in all organisms analyzed so far. Here, it is shown that the closely related enzymes of Homo sapiens and Escherichia coli differ substantially in their substrate preferences for the incorporation of CTP and ATP. While both enzymes require helical structures (mimicking the upper part of tRNAs) for C addition, the data indicate that the E. coli enzyme--in contrast to the human version--is quite promiscuous concerning the incorporation of ATP, where any RNA ending with two C residues is accepted. This feature is consistent with the primary function of the E. coli protein as a repair enzyme. Furthermore, even if the amino acid motif that interacts with the incoming nucleotides in the NTP binding pocket of these enzymes is destroyed and does no longer discriminate between individual bases, both nucleotidyltransferases have a back-up mechanism that ensures CCA addition with considerable accuracy and efficiency in order to guarantee functional protein synthesis and, consequently, the survival of the cell.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
90
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
762-72
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
A comparative analysis of CCA-adding enzymes from human and E. coli: differences in CCA addition and tRNA 3'-end repair.
pubmed:affiliation
University of Leipzig, Institute for Biochemistry, Brüderstrasse 34, D-04103 Leipzig, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't