title: Multidomain and multifunctional glycosyl hydrolases from the extreme thermophile Caldicellulosiruptor isolate Tok7B.1.
abstract: DNA sequencing techniques have revealed widespread molecular diversity of the genomic organization of apparently closely related bacteria (as judged from SSU rDNA sequence similarity). We have previously described the extreme thermophile Caldicellulosiruptor saccharolyticus, which is unusual in possessing multi-catalytic, multidomain arrangements for the majority of its glycosyl hydrolases. We report here the sequencing of three gene clusters of glycosyl hydrolases from Caldicellulosiruptor sp. strain Tok7B.1. These clusters are not closely linked, and each is different in its organization from any described for Cs. saccharolyticus. The catalytic domains of the enzymes belong to glycosyl hydrolase families 5, 9, 10, 43, 44, and 48. The cellulose binding domains (CBDs) of these enzymes from Caldicellulosiruptor sp. Tok7B.1 are types IIIb, IIIc, or VI. A number of individual catalytic and binding domains have been expressed in Escherichia coli, and biochemical data are reported on the purified enzymes for cellulose degradation encoded by engineered derivatives of celB and celE.
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.
authors.forename: M D
authors.initials: MD
authors.lastname: Gibbs
authors.forename: R A
authors.initials: RA
authors.lastname: Reeves
authors.forename: G K
authors.initials: GK
authors.lastname: Farrington
authors.forename: P
authors.initials: P
authors.lastname: Anderson
authors.forename: D P
authors.initials: DP
authors.lastname: Williams
authors.forename: P L
authors.initials: PL
authors.lastname: Bergquist
mesh_terms: D000595:Amino Acid Sequence; D001421:Bacteria, Anaerobic / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases; D005618:Fresh Water / Q000382:microbiology; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014995:Xylosidases / Q000235:genetics / Q000378:metabolism; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C406205:CelE protein, bacteria; D006026:Glycoside Hydrolases; D014995:Xylosidases; D001617:beta-Glucosidase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases; C090001:XynB xylanase