title: Xanthomonas caspase displays an inherent PARP-like activity.
abstract: In an earlier study, intracellular accumulation of metabolites such as pyruvate and citrate in Xanthomonas campestris pv. glycines (Xcg) was found to result in a caspase dependent stationary phase rapid cell death (RCD). In the present study, the presence of poly ADP-ribose polymerase (PARP)-like activity associated with caspase-3-like protein of Xcg is reported. This activity was found to be responsible for depletion of cellular NAD(+) levels in RCD-promoting media such as Luria-Bertani medium and starch medium fortified with citrate. Addition of PARP-specific inhibitors such as 3-aminobenzamide to RCD-promoting media restored the intracellular NAD(+) levels and thereby prevented RCD. The inherent association of PARP-like activity with the caspase protein was demonstrated by PARP cellular assay, immuno-precipitation and Western analysis. A truncated polysaccharide deacetylase gene having a caspase-like domain was cloned. The expressed protein though found to be inactive, cross-reacted with human caspase and PARP antibodies. This is the first report demonstrating the presence of a PARP-like activity in a prokaryote and its involvement in cell death.
authors.affiliation: Food Technology Division, Bhabha Atomic Research Centre, Mumbai, India.
authors.forename: K K
authors.initials: KK
authors.lastname: Raju
authors.forename: H S
authors.initials: HS
authors.lastname: Misra
authors.forename: Arun
authors.initials: A
authors.lastname: Sharma
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000276:immunology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D001549:Benzamides / Q000494:pharmacology; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death; D003001:Cloning, Molecular; D003429:Cross Reactions; D003470:Culture Media / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D016959:Xanthomonas campestris / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D001549:Benzamides; D003470:Culture Media; D004791:Enzyme Inhibitors; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D009243:NAD; C025160:3-aminobenzamide; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases; D000581:Amidohydrolases; C022427:polysaccharide deacetylase