Cleary P P, Handley J, Suvorov A N, Podbielski A, Ferrieri P
Department of Microbiology, University of Minnesota Medical School, Minneapolis 55455.
Infect Immun. 1992 Oct;60(10):4239-44. doi: 10.1128/iai.60.10.4239-4244.1992.
Group B streptococci (GBS) and group A streptococci (GAS) are known to have surface-associated peptidase activity which specifically cleaves C5a (C5a-ase), the primary chemotaxin for polymorphonuclear leukocytes. Amplification products were obtained from GBS genomic DNA template by using the polymerase chain reaction and primers corresponding to the C5a peptidase gene of GAS (scpA12). A restriction map of the GBS full-length amplified gene (scpB) was developed. The scpB restriction map was found to be highly similar to that of the analogous gene in GAS. A 50-bp deletion was located near the 5' end of scpB in a region where repeat sequences are found in scpA12. Hybridization experiments confirmed that other serotypes of GBS also carry an scpB-like gene. These results show that GBS contain a gene, scpB, which is very similar to that harbored by M12 GAS. The probability that scpB encodes the C5a-ase protein is discussed.
已知B族链球菌（GBS）和A族链球菌（GAS）具有与表面相关的肽酶活性，该活性可特异性切割C5a（C5a酶），C5a是多形核白细胞的主要趋化因子。通过聚合酶链反应和与GAS的C5a肽酶基因（scpA12）对应的引物，从GBS基因组DNA模板中获得扩增产物。构建了GBS全长扩增基因（scpB）的限制性图谱。发现scpB限制性图谱与GAS中类似基因的图谱高度相似。在scpB的5'端附近发现一个50 bp的缺失，该区域在scpA12中存在重复序列。杂交实验证实GBS的其他血清型也携带一个类似scpB的基因。这些结果表明GBS含有一个基因scpB，它与M12 GAS所携带的基因非常相似。文中讨论了scpB编码C5a酶蛋白的可能性。
