Linked Life Data

7947832

Source:http://linkedlifedata.com/resource/pubmed/id/7947832

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
1994-12-28
pubmed:abstractText
Class I tRNA synthetases generally contain a characteristic N-terminal catalytic core joined to a C-terminal domain that is idiosyncratic to the enzyme. The closely related class I Escherichia coli methionyl- and isoleucyl-tRNA synthetases each have a single zinc atom coordinated to ligands contained in the catalytic domain. Isoleucyl-tRNA synthetase has a second, functionally essential, zinc bound to ligands at the C-terminal end of the 939 amino acid polypeptide. Recent evidence suggested that this structure curls back and interacts directly or indirectly with the active site. We show here by X-ray absorption spectroscopy that the average Zn environment contains predominantly sulfur ligands with a Zn-S distance of 2.33 A. A model with eight coordinated thiolates divided between two Zn(Cys)4 structures best fit the data which are not consistent with a thiolate-bridged Zn2(Cys)6 structure joining the C-terminal end with the N-terminal active site domain. We also show that zinc bound to the N-terminal catalytic core is important specifically for amino acid binding and utilization, although a direct interaction with zinc is unlikely. We suggest that, in addition to idiosyncratic sequences for tRNA acceptor helix interactions incorporated into the class-defining catalytic domain common to class I enzymes, the architecture of at least some parts of the amino acid binding sites may differ from enzyme to enzyme and include motifs that bind zinc.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14213-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Thiol ligation of two zinc atoms to a class I tRNA synthetase: evidence for unshared thiols and role in amino acid binding and utilization.
pubmed:affiliation
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't