• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文OA文献 >SclA, a Novel Collagen-Like Surface Protein of Streptococcus pyogenes
【2h】

SclA, a Novel Collagen-Like Surface Protein of Streptococcus pyogenes

机译：SclA，化脓性链球菌的新型胶原样表面蛋白

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Surface proteins of Streptococcus pyogenes are important virulence factors. Here we describe a novel collagen-like surface protein, designated SclA (streptococcal collagen-like surface protein). The sclA gene was identified in silico using the Streptococcal Genome Sequencing Project with the recently identified protein GRAB as the probe. SclA has a signal sequence and a cell wall attachment region containing the prototypic LPXTGX motif. The surface-exposed part of SclA contains a unique NH2-terminal domain of 73 amino acids, followed by a collagen-like region. The sclA gene was found to be positively regulated by Mga, a transcriptional activator of several S. pyogenes virulence determinants. A mutant lacking cell wall-associated SclA was constructed and was found to be as effective as wild-type bacteria in platelet aggregation, survival in fresh human blood, and adherence to pharyngeal cells. The sclA gene was found in all 12 S. pyogenes strains that were investigated using PCR. Sequence analysis revealed that the signal sequence and the cell wall attachment region are highly conserved. The collagen-like domain is variable in its NH2-terminal region and has conserved repeated domains in its COOH-terminal part. SclA proteins from most strains have additional proline-rich repeats spacing the collagen-like domain and the cell wall attachment sequence. The unique NH2-terminal region is hypervariable, but computer predictions indicate a common secondary structure, with two alpha helices connected by a loop region. Immune selection may explain the hypervariability in the NH2-terminal region, whereas the preserved secondary structure implies that this region has a common function. These features and the Mga regulation are shared with the M protein of S. pyogenes. Moreover, as with the gene encoding the M protein, phylogenetic analysis indicates that horizontal gene transfer has contributed to the evolution of sclA.
机译：化脓性链球菌的表面蛋白是重要的毒力因子。在这里，我们描述了一种新型的类胶原蛋白表面蛋白，称为SclA（链球菌类胶原蛋白表面蛋白）。使用链球菌基因组测序计划以最近鉴定的蛋白质GRAB作为探针，通过计算机技术鉴定了sclA基因。 SclA具有信号序列和包含原型LPXTGX基序的细胞壁附着区。 SclA的表面暴露部分包含独特的73个氨基酸的NH2末端结构域，其后是胶原样区域。发现sclA基因受到Mga的正调控，Mga是化脓性链球菌毒力决定因素的转录激活因子。构建了一种与细胞壁相关的SclA缺失的突变体，发现该突变体在血小板聚集，在新鲜人血中的存活以及对咽细胞的粘附方面与野生型细菌一样有效。在使用PCR研究的所有12种化脓性链球菌菌株中发现了sclA基因。序列分析表明，信号序列和细胞壁附着区域是高度保守的。胶原样结构域在其NH 2末端区域是可变的，并且在其COOH末端部分具有保守的重复结构域。来自大多数菌株的SclA蛋白具有额外的富含脯氨酸的重复序列，间隔了胶原样结构域和细胞壁附着序列。独特的NH2末端区域是高变的，但计算机预测表明共有一个二级结构，其中两个α螺旋通过一个环区连接。免疫选择可能解释了NH2末端区域的高变异性，而保留的二级结构暗示该区域具有共同的功能。这些特征和Mga调节与化脓性链球菌的M蛋白共有。此外，与编码M蛋白的基因一样，系统发育分析表明水平基因转移已促进sclA的进化。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号