Chen C C, Cleary P P
Department of Microbiology, University of Minnesota School of Medicine, Minneapolis 55455.
J Biol Chem. 1990 Feb 25;265(6):3161-7.
Streptococcal C5a peptidase (SCP), a recently discovered virulence factor of Streptococcus pyogenes, specifically cleaves the human serum chemotaxin C5a near its carboxyl terminus, destroying its ability to serve as a chemoattractant. We previously localized the SCP gene, scpA, to the 5.8-kb insert of the recombinant plasmid pTT1. Here we present the complete nucleotide sequence of scpA and its flanking regions. The gene initiates at a TTG codon and consists of 3501 base pairs, specifying a precursor protein of 128,252 daltons. Sequences resembling the promoter and ribosome-binding site of Gram-positive organisms are found upstream of scpA. The predicted amino acid sequence reveals the presence of a 31-residue signal peptide, putative cell wall spanning and membrane anchor domains. Regions of SCP show significant similarity to the sequences involved in the formation of the active site of the prokaryotic serine protease subtilisin. Results of Southern hybridization studies indicate that sequences highly similar to that of scpA are present in all serotypes of S. pyogenes tested.
链球菌C5a肽酶（SCP）是化脓性链球菌最近发现的一种毒力因子，它能在人血清趋化因子C5a的羧基末端附近特异性切割，破坏其作为趋化因子的能力。我们之前将SCP基因scpA定位到重组质粒pTT1的5.8kb插入片段上。在此，我们展示scpA及其侧翼区域的完整核苷酸序列。该基因起始于一个TTG密码子，由3501个碱基对组成，编码一个128252道尔顿的前体蛋白。在scpA上游发现了类似于革兰氏阳性菌启动子和核糖体结合位点的序列。预测的氨基酸序列显示存在一个31个残基的信号肽、假定的跨细胞壁和膜锚定结构域。SCP的区域与原核丝氨酸蛋白酶枯草杆菌蛋白酶活性位点形成所涉及的序列有显著相似性。Southern杂交研究结果表明，在所有测试的化脓性链球菌血清型中都存在与scpA高度相似的序列。
