Linked Life Data

8632006

Source:http://linkedlifedata.com/resource/pubmed/id/8632006

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1996-7-2
pubmed:abstractText
This report describes the analysis of a novel mutant human factor IX protein from a patient with hemophilia B (factor IX activity <1%; factor IX antigen 45%). Enzymatic amplification of all eight exons of the factor IX gene followed by direct sequence analysis reveals a single nucleotide change (a guanine --> adenine transition) in exon 2 at nucleotide 6409 which results in a glycine --> arginine substitution at amino acid 12 in the gamma-carboxyglutamic acid rich (Gla) domain of the mature protein. Factor IX was isolated by immunoaffinity chromatography from plasma obtained from the proband. The purified protein is indistinguishable from normal factor IX by polyacrylamide gel electrophoresis. Characterization of the variant in purified component assays reveals that it is activated normally by its physiologic activator factor XIa, but its phospholipid-dependent activation by the factor VIIa-tissue factor complex is diminished. In the presence of phospholipid and 5 mM Ca2+, the activities of variant and normal plasma-derived factor IX are similar; however, in the presence of activated factor VIIIa (intrinsic tenase complex), the normal augmentation of the cleavage of the specific substrate of factor IX, factor X, is not observed. The determination of the association constants for normal and variant factor IXa with factor VIIIa shows that the affinity of the activated variant factor IX for the cofactor factor VIIIa is 172-fold lower than normal. Competition studies using active site-inactivated factor IXas in the intrinsic tenase complex confirm that the defect in the variant protein is in its binding to factor VIIIa. We conclude that the structural integrity of the Gla domain of human factor IX is critical for the normal binding of factor IXa to factor VIIIa in the intrinsic tenase complex. In addition, a glycine at amino acid 12 is necessary for normal activation of factor IX by the factor VIIa-tissue factor complex.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3869-76
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:8632006-Adenine, pubmed-meshheading:8632006-Amino Acid Sequence, pubmed-meshheading:8632006-Arginine, pubmed-meshheading:8632006-Base Sequence, pubmed-meshheading:8632006-Binding Sites, pubmed-meshheading:8632006-DNA, pubmed-meshheading:8632006-DNA Mutational Analysis, pubmed-meshheading:8632006-Exons, pubmed-meshheading:8632006-Factor IX, pubmed-meshheading:8632006-Factor IXa, pubmed-meshheading:8632006-Factor VIIIa, pubmed-meshheading:8632006-Factor X, pubmed-meshheading:8632006-Glycine, pubmed-meshheading:8632006-Guanine, pubmed-meshheading:8632006-Hemophilia B, pubmed-meshheading:8632006-Humans, pubmed-meshheading:8632006-Kinetics, pubmed-meshheading:8632006-Mathematics, pubmed-meshheading:8632006-Models, Theoretical, pubmed-meshheading:8632006-Molecular Sequence Data, pubmed-meshheading:8632006-Point Mutation, pubmed-meshheading:8632006-Prothrombin Time, pubmed-meshheading:8632006-Triazines
pubmed:year
1996
pubmed:articleTitle
Structural integrity of the gamma-carboxyglutamic acid domain of human blood coagulation factor IXa Is required for its binding to cofactor VIIIa.
pubmed:affiliation
Department of Pediatrics, University of Pennsylvania, Philadelphia, 19104, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't