title: A novel thermophilic pectate lyase containing two catalytic modules of Clostridium stercorarium.
abstract: The Clostridium stercorarium F-9 pel9A gene encodes a pectate lyase Pel9A consisting of 1,240 amino acids with a molecular weight of 135,171. The mature form of Pel9A is a modular enzyme composed of two family-9 catalytic modules of polysaccharide lyases, CM9-1 and CM9-2, in order from the N terminus. Pel9A showed an overall sequence similarity to the hypothetical pectate lyase PelX of Bacillus halodurans (sequence identity 53%), and CM9-2 showed moderate sequence similarities to some pectate lyases of family 9. Sequence identity between CM9-1 and CM9-2 was 21.3%. The full-length Pel9A lacking the N-terminal signal peptide was expressed, purified, and characterized. The enzyme required Ca(2+) ion for its enzyme activity and showed high activity toward polygalacturonic acid but lower activity toward pectin, indicating that Pel9A is a pectate lyase. Immunological analysis using an antiserum raised against the purified enzyme indicated that Pel9A is constitutively synthesized by C. stercorarium F-9.
authors.affiliation: Faculty of Bioresources, Mie University, Japan.
authors.lastname: Si Si Hla
authors.forename: Junji
authors.initials: J
authors.lastname: Kurokawa
authors.lastname: Suryani
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kimura
authors.forename: Kunio
authors.initials: K
authors.lastname: Ohmiya
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sakka
mesh_terms: D002118:Calcium; D020134:Catalytic Domain; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology*; D007700:Kinetics; D010368:Pectins / Q000378:metabolism; D011133:Polysaccharide-Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017385:Sequence Homology; D013379:Substrate Specificity
chemical_list: D010368:Pectins; D011133:Polysaccharide-Lyases; C023911:pectate lyase; D002118:Calcium; C003181:polygalacturonic acid