Molecular bases for human complement C7 polymorphisms, C7*3 and C7*4.
Complement C7 is one of the components of membrane attack complex (MAC) generated by the terminal complement cascade. C7 protein is polymorphic and most of its polymorphisms have been identified using isoelectric focusing (IEF), which detects protein charge differences. To date, the molecular bases of the polymorphisms detected by IEF have not been determined. In this paper, we describe the structural bases of two C7 IEF-detected polymorphisms, C7*3 and C7*4, both of which are common in Asian populations. C7*3 resulted from substitution of cysteine (Cys) at amino acid residue 106 by charged arginine (Arg; C106R), while charged lysine (Lys) at amino acid residue 398 was replaced by neutral glutamine (Gln; K398Q) in C7*4. As C7*3 is hypomorphic, it is important to study its possible associations with diseases such as immunological disorders and infections. We present genetic bases for this C7 polymorphism, which we determined using polymerase chain reaction (PCR)-based genotyping, a simple and accurate method suitable for large-scale studies.
Horiuchi
Takahiko
T
Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan. horiuchi@intmed1.med.kyushu-u.ac.jp
Nishimukai
Hiroaki
H
Okiura
Tatsuyuki
T
Nishimura
Koji
K
Nishizaka
Hiroaki
H
Kojima
Takeshi
T
Tsukamoto
Hiroshi
H
Hayashi
Kenshi
K
Harada
Mine
M
D001483:Base Sequence; D003184:Complement C7 / Q000235:genetics*; D017931:DNA Primers; D006801:Humans; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational
D003184:Complement C7; D017931:DNA Primers