Linked Life Data

3290685

Source:http://linkedlifedata.com/resource/pubmed/id/3290685

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6176
pubmed:dateCreated
1988-7-29
pubmed:abstractText
The trp repressor is a small dimeric regulatory protein which controls the expression of three operons in Escherichia coli. The inactive aporepressor protein must bind two molecules of L-tryptophan to form the active repressor. If desamino analogues of L-tryptophan such as indole propionate (IPA) are substituted for L-tryptophan, an inactive pseudorepressor is formed. Because the desamino analogues thus cause derepression of operons under control of the trp repressor, they appear to be 'inducers'. We have determined the crystal structure of the pseudorepressor and refined it to 1.65 A. The molecular structure was compared to that of the nearly isomorphous orthorhombic form of the repressor. Surprisingly, the indole ring of IPA is in the same position as the indole ring of L-tryptophan in the repressor, but is 'flipped over'. As a result, the carboxyl group of IPA is oriented toward the DNA-binding surface of the protein and is in a position where it sterically and electrostatically repels the phosphate backbone of both operator and non-operator DNA. This explains why IPA acts as an apparent trp inducer.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
333
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
869-71
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
The structure of trp pseudorepressor at 1.65A shows why indole propionate acts as a trp 'inducer'.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't