Crystal structure of the β‐glycosidase from the hyperthermophile Thermosphaera aggregans: insights into its activity and thermostability

FEBS Letters

Kim, Sung-Hou²  Chi, Young-In²  Jancarik, Jarmalia²  Robertson, Dan E¹  Martinez-Cruz, Luis A²  Swanson, Ronald V¹ 

[1] Diversa Corp., San Diego, CA 92121, USA;Department of Chemistry and Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA

关键词: β-Glycosidase;    Crystal structure;    Glycosyl hydrolase;    Hyperthermophile;    Thermostability;   

DOI  :  10.1016/S0014-5793(99)00090-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The glycosyl hydrolases are an important group of enzymes that are responsible for cleaving a range of biologically significant carbohydrate compounds. Structural information on these enzymes has provided useful information on their molecular basis for the functional variations, while the characterization of the structural features that account for the high thermostability of proteins is of great scientific and biotechnological interest. To these ends we have determined the crystal structure of the β-glycosidase from a hyperthermophilic archeon Thermosphaera aggregans. The structure is a (β/α)₈ barrel (TIM-barrel), as seen in other glycosyl hydrolase family 1 members, and forms a tetramer. Inspection of the active site and the surrounding area reveals two catalytic glutamate residues consistent with the retaining mechanism and the surrounding polar and aromatic residues consistent with a monosaccharide binding site. Comparison of this structure with its mesophilic counterparts implicates a variety of structural features that could contribute to the thermostability. These include an increased number of surface ion pairs, an increased number of internal water molecules and a decreased surface area upon forming an oligomeric quaternary structure.

【 授权许可】

Unknown