Sackstein R, Colten H R, Woods D E
J Biol Chem. 1983 Dec 10;258(23):14693-7.
The complement protein factor B is a novel serine protease which is encoded within the major histocompatibility complex in man, guinea pig, and mouse. To determine the structure of mouse factor B, cDNA clones were isolated from mouse strains of two different major histocompatibility complex haplotypes, H-2k and H-2d, and clones of 0.9 and 1.5 kilobases, respectively, were sequenced. The H-2d clone includes the H-2k clone sequence and spans 94% of the Bb-coding sequence. No differences in sequence or in restriction enzyme sites were observed between the H-2k and H-2d clones. The H-2d clone displays 83% nucleotide homology and 83% (derived) amino acid homology with that of human factor B; there are no insertions or deletions. Comparison of the mouse and human factor B sequence reveals extensive regional homology at the catalytic residues and in the NH2-terminal portion of the Bb fragment.
补体蛋白因子B是一种新型丝氨酸蛋白酶，在人类、豚鼠和小鼠的主要组织相容性复合体中编码。为了确定小鼠因子B的结构，从两种不同主要组织相容性复合体单倍型H-2k和H-2d的小鼠品系中分离出cDNA克隆，并分别对0.9和1.5千碱基的克隆进行测序。H-2d克隆包含H-2k克隆序列，跨越Bb编码序列的94%。在H-2k和H-2d克隆之间未观察到序列或限制性酶切位点的差异。H-2d克隆与人类因子B的核苷酸同源性为83%，氨基酸同源性为83%（推导）；没有插入或缺失。小鼠和人类因子B序列的比较显示，在催化残基和Bb片段的NH2末端部分存在广泛的区域同源性。
