3AYR

GH5 endoglucanase EglA from a ruminal fungus

Summary for 3AYR

• Entry DOI: 10.2210/pdb3ayr/pdb
• Related: 1EDG 3AYS
• Descriptor: Endoglucanase (2 entities in total)
• Functional Keywords: tim barrel, hydrolase, carbohydrate/sugar binding
• Biological source: Piromyces rhizinflatus
• Total number of polymer chains: 1
• Total formula weight: 43377.31

Authors

Tseng, C.-W.,Ko, T.-P.,Guo, R.-T.,Liu, J.-R. (deposition date: 2011-05-16, release date: 2011-11-02, Last modification date: 2024-10-16)

Primary citation

Tseng, C.-W.,Ko, T.-P.,Guo, R.-T.,Huang, J.-W.,Wang, H.-C.,Huang, C.-H.,Cheng, Y.-S.,Wang, A.H.-J.,Liu, J.-R.
Substrate binding of a GH5 endoglucanase from the ruminal fungus Piromyces rhizinflata.
Acta Crystallogr.,Sect.F, 67:1189-1194, 2011

PubMed Abstract: The endoglucanase EglA from Piromyces rhizinflata found in cattle stomach belongs to the GH5 family of glycoside hydrolases. The crystal structure of the catalytic domain of EglA shows the (β/α)(8)-barrel fold typical of GH5 enzymes. Adjacent to the active site of EglA, a loop containing a disulfide bond not found in other similar structures may participate in substrate binding. Because the active site was blocked by the N-terminal His tag of a neighbouring protein molecule in the crystal, enzyme-substrate complexes could not be obtained by soaking but were prepared by cocrystallization. The E154A mutant structure with a cellotriose bound to the -3, -2 and -1 subsites shows an extensive hydrogen-bonding network between the enzyme and the substrate, along with a stacking interaction between Trp44 and the -3 sugar. A possible dimer was observed in the crystal structure, but retention of activity in the E242A mutant suggested that the enzyme probably does not function as a dimer in solution. On the other hand, the first 100 amino acids encoded by the original cDNA fragment are very similar to those in the last third of the (β/α)(8)-barrel fold, indicating that EglA comprises at least two catalytic domains acting in tandem.

PubMed: 22102024
DOI: 10.1107/S1744309111032428

Experimental method

X-RAY DIFFRACTION (2 Å)