• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Infection and immunity >Serine Protease PrtA from Streptococcus pneumoniae Plays a Role in the Killing of S. pneumoniae by Apolactoferrin
【24h】

Serine Protease PrtA from Streptococcus pneumoniae Plays a Role in the Killing of S. pneumoniae by Apolactoferrin

机译：肺炎链球菌丝氨酸蛋白酶PrtA在Apolactoferrin杀死肺炎链球菌中起作用

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

It is known that apolactoferrin, the iron-free form of human lactoferrin, can kill many species of bacteria, including Streptococcus pneumoniae. Lactoferricin, an N-terminal peptide of apolactoferrin, and fragments of it are even more bactericidal than apolactoferrin. In this study we found that apolactoferrin must be cleaved by a serine protease in order for it to kill pneumococci. The serine protease inhibitors were able to block killing by apolactoferrin but did not block killing by a lactoferrin-derived peptide. Thus, the killing of pneumococci by apolactoferrin appears to require a protease to release a lactoferricin-like peptide(s). Incubation of apolactoferrin with growing pneumococci resulted in a 12-kDa reduction in its molecular mass, of which about 7 to 8 kDa of the reduction was protease dependent. Capsular type 2 and 19F strains with mutations in the gene encoding the major cell wall-associated serine protease, prtA, lost much of their ability to degrade apolactoferrin and were relatively resistant to killing by apolactoferrin (P < 0.001). Recombinant PrtA was also able to cleave apolactoferrin, reducing its mass by about 8 kDa, and greatly enhance the killing activity of the solution containing the apolactoferrin and its cleavage products. Mass spectroscopy revealed that PrtA makes a major cut between amino acids 78 and 79 of human lactoferrin, removing the N-terminal end of the molecule (about 8.6 kDa). The simplest interpretation of these data is that the mechanism by which apolactoferrin kills Streptococcus pneumoniae requires the release of a lactoferricin-like peptide(s) and that it is this peptide(s), and not the intact apolactoferrin, which kills pneumococci.
机译：众所周知，人乳铁蛋白的无铁形式脱铁铁蛋白可以杀死许多细菌，包括肺炎链球菌。乳铁蛋白，一种无铁蛋白的N末端肽，其片段比无铁蛋白具有更大的杀菌作用。在这项研究中，我们发现脱铁乳铁蛋白必须被丝氨酸蛋白酶切割才能杀死肺炎球菌。丝氨酸蛋白酶抑制剂能够阻止脱铁铁蛋白的杀伤，但不能阻止乳铁蛋白衍生的肽的杀伤。因此，用无铁乳铁蛋白杀死肺炎球菌似乎需要蛋白酶释放乳铁蛋白样肽。用不断增长的肺炎链球菌温育过磷酸铁铁蛋白会导致其分子量降低12 kDa，其中约7至8 kDa的降低是蛋白酶依赖性的。荚膜2型和19F菌株在编码主要细胞壁相关丝氨酸蛋白酶prtA的基因中发生突变，丧失了降解Apolacterferrin的能力，并且对Apolactoferrin的杀伤能力相对较弱（P <0.001）。重组PrtA还能够裂解铜铁蛋白，使其质量减少约8kDa，并大大增强了含有铜铁蛋白及其裂解产物的溶液的杀伤活性。质谱分析表明，PrtA在人乳铁蛋白的氨基酸78和79之间产生了一个主要切割，去除了该分子的N末端（约8.6 kDa）。对这些数据的最简单解释是，阿魏铜铁蛋白杀死肺炎链球菌的机理要求释放乳铁蛋白样肽，而该肽而不是完整的古铜铁蛋白可以杀死肺炎球菌。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

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