1. Gene cloning, expression, and X-ray crystallographic analysis of a β-mannanase from Eisenia fetida.
- Author
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Ueda, Mitsuhiro, Hirano, Yu, Fukuhara, Hiroaki, Naka, Yuki, Nakazawa, Masami, Sakamoto, Tatsuji, Ogata, Yoshiyuki, and Tamada, Taro
- Subjects
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EISENIA (Algae) , *CLONING , *GENE expression , *X-ray crystallography , *AMINO acids - Abstract
The endo-1,4-β-mannanases (Ef-Man) gene from Eisenia fetida was determined to consist of 1131 bp and encode a 377 amino acid protein. The amino acid sequence showed similarity with the endo-1,4-β-mannanases of Daphnia pulex (62%), Cryptopygus antarcticus (64%), Crassostrea gigas (61%), Mytilus edulis (60%), and Aplysia kurodai (58%). The gene encoding mature Ef-Man was expressed in Pichia pastoris (GS115 strain). Based on SDS-PAGE analysis, the molecular mass of the purified recombinant Ef-Man (rEf-Man) was estimated to be 39 kDa. All catalytically important residues of endo-1,4-β-mannanases in the glycoside hydrolase (GH) family 5 were conserved in Ef-Man. The optimal temperature for rEf-Man was identified as 60 °C. HPLC and HPAEC analyses suggest that Ef-Man requires at least six subsites for efficient hydrolysis and is capable of performing transglycosylation reactions. The overall structure of rEf-Man is similar to those of GH5 family proteins, and tertiary structures around the active site are conserved among endo-1,4-β-mannanase families. X-ray crystallographic analysis supports the hydrolysis and transglycosylation reaction mechanism determined by HPLC and HPAEC analyses. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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