Linked Life Data

18620542

Source:http://linkedlifedata.com/resource/pubmed/id/18620542

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2008-10-9
pubmed:abstractText
Class I adenylate cyclases are found in gamma- and delta-proteobacteria. They play central roles in processes such as catabolite repression in Escherichia coli or development of full virulence in pathogens such as Yersinia enterocolitica and Vibrio vulnificus. The catalytic domain (residues 2-446) of the adenylate cyclase of E. coli was overexpressed and purified. It displayed a V(max) of 665 nmol of cAMP x mg(-1) x min(-1) and a K(m) of 270 microM. Titration of the metal cofactor Mg(2+) against the substrate ATP showed a requirement for free metal ions in addition to the MgATP complex, suggesting a two-metal-ion mechanism as is known for class II and class III adenylate cyclases. Twelve residues which are essential for catalysis were identified by mutagenesis of a total of 20 polar residues conserved in all class I adenylate cyclases. Five essential residues (Ser(103), Ser(113), Asp(114), Asp(116) and Trp(118)) were part of a region which is found in all members of the large DNA polymerase beta-like nucleotidyltransferase superfamily. Alignment of the E. coli adenylate cyclase with the crystal structure of a distant member of the superfamily, archaeal tRNA CCA-adding enzyme, suggested that Asp(114) and Asp(116) are the metal-cofactor-ion-binding residues. The S103A mutant had a 17-fold higher K(m) than wild-type, demonstrating its important role in substrate binding. In comparison with the tRNA CCA-adding enzyme, Ser(103) of the E. coli adenylate cyclase apparently binds the gamma-phosphate group of ATP. Consistent with this function, the S103A mutation caused a marked reduction of discrimination between ATP- and ADP- or AMP-derived inhibitors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
415
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
449-54
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Structure-function relationships in Escherichia coli adenylate cyclase.
pubmed:affiliation
Department of Pharmacology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA. jul2015@med.cornell.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't