Ripoche J, Day A J, Harris T J, Sim R B
Department of Biochemistry, University of Oxford, U.K.
Biochem J. 1988 Jan 15;249(2):593-602. doi: 10.1042/bj2490593.
The complete amino acid sequence of the human complement system regulatory protein, factor H, has been derived from sequencing three overlapping cDNA clones. The sequence consists of 1213 amino acids arranged in 20 homologous units, each about 60 amino acids long, and an 18-residue leader sequence. The 60-amino-acid-long repetitive units are homologous with those found in a large number of other complement and non-complement proteins. Two basic C-terminal residues, deduced from the cDNA sequence, are absent from factor H isolated from outdated plasma. A tyrosine/histidine polymorphism was observed within the seventh homologous repeat unit of factor H. This is likely to represent a difference between the two major allelic variants of factor H. The nature of the cDNA clones indicates that there is likely to be an alternative splicing mechanism, resulting in the formation of at least two species of factor H mRNA.
人类补体系统调节蛋白H因子的完整氨基酸序列是通过对三个重叠的cDNA克隆进行测序得出的。该序列由1213个氨基酸组成，排列成20个同源单位，每个单位约60个氨基酸长，还有一个18个残基的前导序列。这60个氨基酸长的重复单位与大量其他补体和非补体蛋白中的重复单位同源。从cDNA序列推导的两个碱性C末端残基在从过期血浆中分离的H因子中不存在。在H因子的第七个同源重复单位内观察到酪氨酸/组氨酸多态性。这可能代表H因子的两个主要等位基因变体之间的差异。cDNA克隆的性质表明可能存在可变剪接机制，导致形成至少两种H因子mRNA。
