Full-length structure of the major autolysin LytA
Full-length structure of the major autolysin LytA
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主要自溶素 LytA 的全长结构。
DOI：
10.1107/s1399004715007403
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发表时间：
2015-06-01
影响因子：
2.2
通讯作者：
Zhou, Cong-Zhao
中科院分区：
文献类型：
--
作者：
Li, Qiong;Cheng, Wang;Zhou, Cong-Zhao
LytA负责许多链球菌属物种的自溶，包括病原体如链球菌。肺炎链球菌（S. pseudopropylacetylacetate和S.缓解。然而，这种主要的自溶素如何实现完全活性仍然未知。这里，S.肺炎LytA二聚体以2.1埃分辨率报告。每个亚基具有N-末端酰胺酶结构域和由六个胆碱结合重复组成的C-末端胆碱结合结构域，其形成五个典型的和一个单层胆碱结合位点。定点诱变与酶活性测定相结合表明，二聚化和结合胆碱是两个独立的要求在体内的自溶活性的LytA。总之，它表明，二聚化和完全占用所有胆碱结合位点，通过结合到含胆碱的TA链使LytA采取一个完全活跃的构象，使酰胺酶域裂解两个lactyl-amide键位于约103埃的肽聚糖。
LytA is responsible for the autolysis of many Streptococcus species, including pathogens such as S. pneumoniae, S. pseudopneumoniae and S. mitis. However, how this major autolysin achieves full activity remains unknown. Here, the full-length structure of the S. pneumoniae LytA dimer is reported at 2.1 angstrom resolution. Each subunit has an N-terminal amidase domain and a C-terminal choline-binding domain consisting of six choline-binding repeats, which form five canonical and one single-layered choline-binding sites. Site-directed mutageneses combined with enzymatic activity assays indicate that dimerization and binding to choline are two independent requirements for the autolytic activity of LytA in vivo. Altogether, it is suggested that dimerization and full occupancy of all choline-binding sites through binding to choline-containing TA chains enable LytA to adopt a fully active conformation which allows the amidase domain to cleave two lactyl-amide bonds located about 103 angstrom apart on the peptidoglycan.