Linked Life Data

9091315

Source:http://linkedlifedata.com/resource/pubmed/id/9091315

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-4-10
pubmed:abstractText
The role of the extra helix alpha zero in the N-terminal extension of the eight-fold beta alpha barrel of indoleglycerol phosphate synthase was probed by point mutation and truncation. Replacing invariant leucine 5 by valine of the enzyme from Escherichia coli affected neither kcat nor Km, but deletion of 8 N-terminal residues decreased solubility strongly. The similarly truncated variant from the hyperthermophile Sulfolobus solfataricus was soluble, and had the same kcat value as the wild-type protein but a 220-fold greater Km value. These results suggest that the N-terminal portion of helix alpha zero provides for strong binding of the substrate, but is not essential for stabilizing the bound transition state. Thus, three enzymes of tryptophan biosynthesis operate essentially as canonical eight-fold beta alpha barrels, as required for their divergent evolution.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
403
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
268-72
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Deletion mutagenesis as a test of evolutionary relatedness of indoleglycerol phosphate synthase with other TIM barrel enzymes.
pubmed:affiliation
Department of Chemistry, University of Minnesota, Minneapolis 55455, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't