Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2000-1-27
pubmed:abstractText
Activated coagulation factor XI (factor XIa) proteolytically cleaves its substrate, factor IX, in an interaction requiring the factor XI A3 domain (Sun, Y., and Gailani, D. (1996) J. Biol. Chem. 271, 29023-29028). To identify key amino acids involved in factor IX activation, recombinant factor XIa proteins containing alanine substitutions for wild-type sequence were expressed in 293 fibroblasts and tested in a plasma clotting assay. Substitutions for Ile(183)-Val(191) and Ser(195)-Ile(197) at the N terminus and for Ser(258)-Ser(264) at the C terminus of the A3 domain markedly decreased factor XI coagulant activity. The plasma protease prekallikrein is structurally homologous to factor XI, but activated factor IX poorly. A chimeric factor XIa molecule with the A3 domain replaced with A3 from prekallikrein (FXI/PKA3) activated factor IX with a K(m) 35-fold greater than that of wild-type factor XI. FXI/PKA3 was used as a template for a series of proteins in which prekallikrein A3 sequence was replaced with factor XI sequence to restore factor IX activation. Clotting and kinetics studies using these chimeras confirmed the results obtained with alanine mutants. Amino acids between Ile(183) and Val(191) are necessary for proper factor IX activation, but additional sequence between Ser(195) and Ile(197) or between Phe(260) and Ser(265) is required for complete restoration of activation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
274
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
36373-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Identification of amino acids in the factor XI apple 3 domain required for activation of factor IX.
pubmed:affiliation
Departments of Pathology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6305, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.