title: Characterization and gene cloning of a cold-active cellulase from a deep-sea psychrotrophic bacterium Pseudoalteromonas sp. DY3.
abstract: The celX gene encoding an extracellular cold-active cellulase was isolated from a psychrotrophic bacterium, which was isolated from deep-sea sediment and identified as a Pseudoalteromonas species. It encoded a protein consisting of 492 amino acids with a calculated molecular mass of 52.7 kDa. The CelX consisted of an N-terminal catalytic domain belonging to glycoside hydrolase family 5 and a C-terminal cellulose-binding domain belonging to carbohydrate-binding module family 5. The long linker sequence connecting both domains was composed of 105 residues. The optimal temperature for cellulase activity of CelX was 40 degrees C. The enzyme was most active at pH 6-7 and showed better resistance to alkaline condition. The zymogram activity analysis indicated that the CelX consisted of single enzyme component. The cellobiose was main hydrolysate of CelX.
authors.affiliation: Third Institute of Oceanography, Key Laboratory of Marine Biogenetic Resources, State Oceanic Administration, Daxue road 178#, 361005, Xiamen, Fujian, China. runyingzeng@yahoo.com.cn
authors.forename: Runying
authors.initials: R
authors.lastname: Zeng
authors.forename: Pengjun
authors.initials: P
authors.lastname: Xiong
authors.forename: Jianjun
authors.initials: J
authors.lastname: Wen
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002480:Cellulase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D031161:Pseudoalteromonas / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D012623:Seawater / Q000382:microbiology; D017386:Sequence Homology, Amino Acid
chemical_list: D004269:DNA, Bacterial; D002480:Cellulase