Structural highlights
FunctionALYS_STRPN Autolysins are involved in some important biological processes such as cell separation, cell-wall turnover, competence for genetic transformation, formation of the flagella and sporulation. Autolysin strictly depends on the presence of choline-containing cell walls for activity. Publication Abstract from PubMedLytA 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 A 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 A apart on the peptidoglycan. Full-length structure of the major autolysin LytA.,Li Q, Cheng W, Morlot C, Bai XH, Jiang YL, Wang W, Roper DI, Vernet T, Dong YH, Chen Y, Zhou CZ Acta Crystallogr D Biol Crystallogr. 2015 Jun;71(Pt 6):1373-81. doi:, 10.1107/S1399004715007403. Epub 2015 May 23. PMID:26057677[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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