title: Full-length structure of the major autolysin LytA.
abstract: 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 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 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 Å apart on the peptidoglycan.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Wang
authors.initials: W
authors.lastname: Cheng
authors.affiliation: Universite Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Morlot
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Xiao Hui
authors.initials: XH
authors.lastname: Bai
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Yong Liang
authors.initials: YL
authors.lastname: Jiang
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, England.
authors.forename: David I
authors.initials: DI
authors.lastname: Roper
authors.affiliation: Universite Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027 Grenoble, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Vernet
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
authors.forename: Yu Hui
authors.initials: YH
authors.lastname: Dong
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Cong Zhao
authors.initials: CZ
authors.lastname: Zhou
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry*; D011487:Protein Conformation; D013291:Streptococcus / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D009238:N-Acetylmuramoyl-L-alanine Amidase
keywords: Streptococcus pneumoniae; autolysin; choline-binding sites; crystal structure; dimerization; peptidoglycan