DOI: 10.5176/2301-3761_CCECP18.27
Authors: A.Martynova-Van Kley, J. Del Aguila, A. Nalian
Abstract:
Pyrococcus horikoshii has an optimal growth temperature of 97˚C [5]. The open reading frame PH1171 was identified as a homolog to endoglucanase from glycoside hydrolase family 5 (Cel5A) with the closest relative from Acidotermus cellulolyticus (EGAc) [1]. Due to the similarity between the amino acid sequences of endoglucanase from P. horikoshii (EGPh) and EGAc, EGPh is also an endoglucanase which hydrolyzes β (1→4) glycosidic bonds and belongs to the Cel5A family. The catalytic activity and increased thermostablility of EGPh were experimentally demonstrated by Ando et al. [1]. The amino acid sequence alignment of EGPh with known homologous sequences shows seven conserved residues Arg62, His116, Asn161, Glu162, His238, Tyr240, Glu282 [10] where Glu162 is the proton donor [3] and Glu282 is the nucleophile [9] in the catalytic site, characteristic to GH5 family of endoglucanases. Because of its ability to hydrolyze cellulose at 97˚C, EGPh is expected to be an excellent enzyme for the industrial hydrolysis of cellulose [6].
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