1QHZ
NATIVE TETRAGONAL STRUCTURE OF THE ENDOGLUCANASE CEL5A FROM BACILLUS AGARADHAERENS
Summary for 1QHZ
| Entry DOI | 10.2210/pdb1qhz/pdb |
| Related | 1QI0 1QI2 |
| Descriptor | ENDOGLUCANASE B, CALCIUM ION (3 entities in total) |
| Functional Keywords | hydrolase, cellulose degradation, endoglucanase, glycoshydrolase family 5 |
| Biological source | Bacillus agaradhaerens |
| Total number of polymer chains | 1 |
| Total formula weight | 34396.65 |
| Authors | Varrot, A.,Schulein, M.,Davies, G.J. (deposition date: 1999-06-02, release date: 2000-06-07, Last modification date: 2023-08-16) |
| Primary citation | Varrot, A.,Schulein, M.,Davies, G.J. Insights into ligand-induced conformational change in Cel5A from Bacillus agaradhaerens revealed by a catalytically active crystal form. J.Mol.Biol., 297:819-828, 2000 Cited by PubMed Abstract: Glycoside hydrolases are ubiquitous enzymes involved in a diverse array of biological processes, from the breakdown of biomass, through to viral invasion and cellular signalling. Endoglucanase Cel5A from Bacillus agaradhaerens, classified into glycoside hydrolase family 5, has been studied in a catalytically inactive crystal form at low pH conditions, in which native and complex structures revealed the importance of ring distortion during catalysis. Here, we present the structure of Cel5A in a new crystal form obtained at higher pH values in which the enzyme is active "in-crystal". Native, cellotriosyl-enzyme intermediate and beta-d-cellobiose structures were solved at 1.95, 1.75 and 2.1 A resolution, respectively. These structures reveal two classes of conformational change: those caused by crystal-packing and pH, with others induced upon substrate binding. At pH 7 a histidine residue, His206, implicated in substrate-binding and catalysis, but previously far removed from the substrate-binding cleft, moves over 10 A into the active site cleft in order to interact with the substrate in the +2 subsite. Occupation of the -1 subsite by substrate induces a loop closure to optimise protein-ligand interactions. Cel5A, along with the unrelated family 45 and family 6 cellulases, provides further evidence of substantial conformational change in response to ligand binding for this class of hydrolytic enzyme. PubMed: 10731432DOI: 10.1006/jmbi.2000.3567 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.95 Å) |
Structure validation
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