ISSN:
0730-2312
Schlagwort(e):
protein C
;
factor IX
;
coagulation
;
methylation
;
methyl cytosine
;
intron
;
serine protease
;
evolution
;
mutation
;
gene structure
;
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Biologie
,
Chemie und Pharmazie
,
Medizin
Notizen:
Human protein C is a vitamin K-dependent plasma protein that serves as a feedback down-regulator of the coagulation cascade by specifically degrading the protein cofactors VIIIa and Va. The protein C precursor consists of the following domains: leader peptide, “gla” region, two epidermal growth factor segments, and the activation peptide/serine protease. Comparison of amino acid sequences reveals that protein C and factor IX are homologous. A comparison of the genes for protein C and factor IX shows that all seven of the introns within the protein coding regions are in identical positions and correspond to protein structure-function domain boundries. However, the base compositions of the two genes (coding and noncoding regions) are remarkably different: ∼60% guanine + cytosine (G + C) for protein C versus ∼40% G + C for factor IX. One possible explanation for this phenomenon is that the factor IX gene (located on the X chromosome) has undergone extensive deoxycytosine methylation and subsequent spontaneous deamination mutagenesis, resulting in a net C to thymine (and G to adenine) transition. This would suggest that the protein C gene may represent a more primitive form of the gene duplication precursor.
Zusätzliches Material:
2 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jcb.240330305
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