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          Institute: MPI für medizinische Forschung     Collection: Abteilung Biomolekulare Mechanismen     Display Documents



ID: 350141.0, MPI für medizinische Forschung / Abteilung Biomolekulare Mechanismen
Molecular and structural characterization of the PezAT chromosomal toxin−antitoxin system of the human pathogen Streptococcus pneumoniae
Translation of Title:Molecular and structural characterization of the PezAT chromosomal toxin−antitoxin system of the human pathogen Streptococcus pneumoniae
Authors:Khoo, Seok Kooi; Loll, Bernhard; Chan, Wai Ting; Shoeman, Robert L.; Ngoo, Lena; Yeo, Chew Chieng; Meinhart, Anton
Language:English
Date of Publication (YYYY-MM-DD):2007-07-06
Title of Journal:Journal of Biological Chemistry
Journal Abbrev.:J. Biol. Chem.
Volume:282
Issue / Number:27
Start Page:19606
End Page:19618
Review Status:Peer-review
Audience:Experts Only
Intended Educational Use:No
Abstract / Description:The chromosomal pezT gene of the Gram−positive pathogen Streptococcus pneumoniae encodes a protein that is homologous to the zeta toxin of the Streptococcus pyogenes plasmid pSM19035−encoded epsilon−zeta toxin−antitoxin system. Overexpression of pezT in Escherichia coli led to severe growth inhibition from which the bacteria recovered ˜3 h after induction of expression. The toxicity of PezT was counteracted by PezA which is encoded immediately upstream of pezT and shares weak sequence similarities in the carboxy−terminal region with the epsilon antitoxin. The pezAT genes form a bicistronic operon that is co−transcribed from a sigma 70−like promoter upstream of pezA and is negatively autoregulated with PezA functioning as a transcriptional repressor and PezT as a co−repressor. Both PezA and the non−toxic PezA2PezT2 protein complex bind to a palindrome sequence that overlaps the promoter. This differs from the epsilon−zeta system in which epsilon functions solely as the antitoxin and transcriptional regulation is carried out by another protein designated omega. Results from site−directed mutagenesis experiments demonstrated that the toxicity of PezT is dependent on a highly conserved phosphoryltransferase active site and an ATP/GTP nucleotide binding site. In the PezA2PezT2 complex, PezA neutralizes the toxicity of PezT by blocking the nucleotide binding site through steric hindrance.
Last Change of the Resource (YYYY-MM-DD):--
External Publication Status:published
Document Type:Article
Communicated by:Wulf Kaiser
Affiliations:MPI für medizinische Forschung/Abteilung Biomolekulare Mechanismen
Identifiers:LOCALID:6788
URI:http%3A%2F%2Fwww.jbc.org%2Fcgi%2Freprint%2F282%2F2...
URI:http%3A%2F%2Fwww.jbc.org%2Fcgi%2Fcontent%2Ffull%2F...
URI:http%3A%2F%2Fwww.jbc.org%2Fcgi%2Fcontent%2Fabstrac...
DOI:10.1074%2Fjbc.M701703200%20
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