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KMID : 0545120120220121724
Journal of Microbiology and Biotechnology
2012 Volume.22 No. 12 p.1724 ~ p.1730
Structural Analysis of ¥á-L-Arabinofuranosidase from Thermotoga maritima Reveals Characteristics for Thermostability and Substrate Specificity
Arti Dumbrepatil

Park Jung-Mi
Jung Tae-Yang
Song Hyung-Nam
Jang Myoung-Uoon
Han Nam-Soo
Kim Tae-Jip
Woo Eui-Jeon
Abstract
An ¥á-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.
KEYWORD
Thermotoga maritima, alpha-L-arabinofuranosidase, structural analysis, X-ray crystallography
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