Document Detail


The N-terminal β-sheet of the hyperthermophilic endoglucanase from Pyrococcus horikoshii is critical for thermostability.
MedLine Citation:
PMID:  22344652     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The β-1,4-endoglucanase (EC 3.2.1.4) from the hyperthermophilic archaeon Pyrococcus horikoshii (EGPh) has strong hydrolyzing activity toward crystalline cellulose. When EGPh is used in combination with β-glucosidase (EC 3.2.1.21), cellulose is completely hydrolyzed to glucose at high temperature, suggesting great potential for EGPh in bioethanol industrial applications. The crystal structure of EGPh shows a triosephosphate isomerase (TIM) (β/α)(8)-barrel fold with an N-terminal antiparallel β-sheet at the opposite side of the active site and a very short C-terminal sequence outside of the barrel structure. We describe here the function of the peripheral sequences outside of the TIM barrel core structure. Sequential deletions were performed from both N and C termini. The activity, thermostability, and pH stability of the expressed mutants were assessed and compared to the wild-type EGPh enzyme. Our results demonstrate that the TIM barrel core is essential for enzyme activity and that the N-terminal β-sheet is critical for enzyme thermostability. Bioinformatics analyses identified potential key residues which may contribute to enzyme hyperthermostability.
Authors:
Trent C Yang; Steve Legault; Emery A Kayiranga; Jyothi Kumaran; Kazuhiko Ishikawa; Wing L Sung
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-02-17
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  78     ISSN:  1098-5336     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-04-11     Completed Date:  2012-07-13     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3059-67     Citation Subset:  IM    
Affiliation:
Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Cellulase / chemistry*,  genetics*
Enzyme Stability
Hot Temperature
Hydrogen-Ion Concentration
Molecular Sequence Data
Protein Conformation
Protein Stability
Protein Structure, Tertiary
Pyrococcus horikoshii / enzymology*
Sequence Deletion
Chemical
Reg. No./Substance:
EC 3.2.1.4/Cellulase
Comments/Corrections

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