title: Structural analysis of alpha-L-arabinofuranosidase from Thermotoga maritima reveals characteristics for thermostability and substrate specificity.
abstract: An alpha-L-arabinofuranosidase (TmAFase) from Thermotoga maritima MSB8 is a highly thermostable exo-acting hemicellulase that exhibits a relatively higher activity towards arabinan and arabinoxylan, compared with other glycoside hydrolase 51 family enzymes. In the present study, we carried out the enzymatic characterization and structural analysis of TmAFase. Tight domain associations found in TmAFase, such as an inter-domain disulfide bond (Cys306 and Cys476) in each monomer, a novel extended arm (amino acids 374-385) at the dimer interface, and total 12 salt bridges in the hexamer, may account for the thermostability of the enzyme. One of the xylan binding determinants (Trp96) was identified in the active site, and a region of amino acids (374-385) protrudes out forming an obvious wall at the substrate-binding groove to generate a cavity. The altered cavity shape with a strong negative electrostatic distribution is likely related to the unique substrate preference of TmAFase towards branched polymeric substrates.
authors.affiliation: Department of Food Science and Technology, Chungbuk National University, Cheongju, Korea.
authors.forename: Arti
authors.initials: A
authors.lastname: Dumbrepatil
authors.forename: Jung-Mi
authors.initials: JM
authors.lastname: Park
authors.forename: Tae Yang
authors.initials: TY
authors.lastname: Jung
authors.forename: Hyung-Nam
authors.initials: HN
authors.lastname: Song
authors.forename: Myoung-Uoon
authors.initials: MU
authors.lastname: Jang
authors.forename: Nam Soo
authors.initials: NS
authors.lastname: Han
authors.forename: Tae-Jip
authors.initials: TJ
authors.lastname: Kim
authors.forename: Eui Jeon
authors.initials: EJ
authors.lastname: Woo
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase