PDBsum entry 1qvb

Hydrolase

PDB id: 1qvb

Contents

Protein chains

481 a.a. *

Waters ×439

* Residue conservation analysis

PDB id:

1qvb

Name:

Hydrolase

Title:

Crystal structure of the beta-glycosidase from the hyperthermophile thermosphaera aggregans

Structure:

Beta-glycosidase. Chain: a, b. Engineered: yes

Source:

Thermosphaera aggregans. Organism_taxid: 54254. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.40Å R-factor: 0.210 R-free: 0.249

Authors:

Y.-I.Chi,L.A.Martinez-Cruz,R.V.Swanson,D.E.Robertson,S.-H.Kim

Key ref:

Y.I.Chi et al. (1999). Crystal structure of the beta-glycosidase from the hyperthermophile Thermosphaera aggregans: insights into its activity and thermostability. Febs Lett, 445, 375-383. PubMed id: 10094493 DOI: 10.1016/S0014-5793(99)00090-3

Date:

07-Jul-99 Release date: 13-Jul-99

Protein chains

Q9YGA8  (Q9YGA8_9CREN) -  Beta-glycosidase from Thermosphaera aggregans

Seq: 481 a.a.

Struc: 481 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/S0014-5793(99)00090-3

Febs Lett 445:375-383 (1999)

PubMed id: 10094493

Crystal structure of the beta-glycosidase from the hyperthermophile Thermosphaera aggregans: insights into its activity and thermostability.

Y.I.Chi, L.A.Martinez-Cruz, J.Jancarik, R.V.Swanson, D.E.Robertson, S.H.Kim.

ABSTRACT

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 beta-glycosidase from a hyperthermophilic archeon Thermosphaera aggregans. The structure is a (beta/alpha)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.

Selected figure(s)

Figure 5.
Fig. 5. Ball and stick representation of the aromatic residues surrounding the active site at the C-terminal end of the TIM-barrel-folded molecule shown as a wire representation. The catalytic residues are also shown as a ball and stick model and labelled.

Figure 6.
Fig. 6. Ball and stick stereo representation of the hydrogen bond network associated with water molecules at the core of the active site. The water molecules are shown in pink.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Febs Lett (1999, 445, 375-383) copyright 1999.

Figures were selected by an automated process.