Full‐length structure of the major autolysin LytA. (1st June 2015)

• Record Type: Journal Article
• Authors: Li, Qiong; Cheng, Wang; Morlot, Cécile; Bai, Xiao‐Hui; Jiang, Yong‐Liang; Wang, Wenjia; Roper, David I.; Vernet, Thierry; Dong, Yu‐Hui; Chen, Yuxing; Zhou, Cong‐Zhao
• Is Part Of: Acta crystallographica. Volume 71:Part 6(2015:Jun.)
• Page Start: 1373
• Page End: 1381
• Publication Date: 2015-06-01
• Subjects: Biomolecules -- Structure -- Periodicals; Physical biochemistry -- Periodicals; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; 572
• DOI: 10.1107/S1399004715007403
• Languages: English
• ISSNs: 0907-4449

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>LytA is responsible for the autolysis of many <italic>Streptococcus</italic> species, including pathogens such as <italic>S. pneumoniae</italic>, <italic>S. pseudopneumoniae</italic> and <italic>S. mitis</italic>. However, how this major autolysin achieves full activity remains unknown. Here, the full‐length structure of the <italic>S. pneumoniae</italic> LytA dimer is reported at 2.1 Å 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 <italic>in vivo</italic>. 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 Å apart on the peptidoglycan.</p> </abstract>