Analysis of Active Center in Hyperthermophilic Cellulase from Pyrococcus horikoshii

  • Kang, Hee-Jin (National Institute of Advanced Industrial Science and Technology (AIST, Kansai)) ;
  • Ishikawa, Kazuhiko (National Institute of Advanced Industrial Science and Technology (AIST, Kansai))
  • Published : 2007.08.30

Abstract

A hyperthermostable endoglucanase from Pyrococcus horikoshii with the capability of hydrolyzing crystalline cellulose was analyzed. A protein engineering study was carried out to obtain a reduced-size mutant. Five amino acid residues at both the N- and C-terminus were found to be removable without any loss of activity or thermal stability. Site-directed mutagenesis was also performed on R102, N200, E201, H297, Y299, E342, and W377, residues possibly involved in the active center or in the recognition and binding of a cellulose substrate. The activity of the resulting mutants was considerably decreased, confirming that the mutated residues were all important for activity. A reduced-size enzyme, as active as the wild-type endoglucanase, was successfully obtained, plus the residues critical for its activity and specificity were confirmed. Consequently, an engineered enzyme with a reduced size was obtained, and the amino acids essential for activity were confirmed by site-directed mutagenesis and comparison with a known three-dimensional structure.

Keywords

References

  1. Ando, S., H. Ishida, Y. Kosugi, and K. Ishikawa. 2002. Hyperthermostable endoglucanase from Pyrococcus horikoshii. Appl. Environ. Microbiol. 68: 430-433 https://doi.org/10.1128/AEM.68.1.430-433.2002
  2. Hiromi, K., Y. Takahashi, and S. Ono. 1963. Kinetics of hydrolytic reaction catalyzed by crystalline bacterial $\alpha$- amylase. The influence of temperature. Bull. Chem. Soc. Jpn 36: 563-569 https://doi.org/10.1246/bcsj.36.563
  3. Kang, H. J., K. Uegaki, H. Fukada, and K. Ishikawa. 2007. Improvement of the enzymatic activity of the hyperthermophilic cellulase from Pyrococcus horikoshii. Extremophiles 11: 251-256 https://doi.org/10.1007/s00792-006-0033-2
  4. Kashima, Y., K. Mori, H. Fukada, and K. Ishikawa. 2005. Analysis of the function of a hyperthermophilic endoglucanase from Pyrococcus horikoshii that hydrolyzes crystalline cellulose. Extremophiles 9: 37-43 https://doi.org/10.1007/s00792-004-0418-z
  5. McCarter, J. D. and S. G. Withers. 1994. Mechanisms of enzymatic glycoside hydrolysis. Curr. Opin. Struct. Biol. 4: 885-892 https://doi.org/10.1016/0959-440X(94)90271-2
  6. Mullis, K., F. Faloona, S. Scharf, R. Saiki, G. Horn, and H. Erlich. 1986. Specific enzymatic amplification of DNA in vitro: The polymerase chain reaction. Cold Spring Harb. Symp. Quant. Biol. 51: 263-273
  7. Percival Zhang, Y. H., M. E. Himmel, and J. R. Mielenz. 2006. Outlook for cellulase improvement: Screening and selection strategies. Biotechnol. Adv. 24: 452-481 https://doi.org/10.1016/j.biotechadv.2006.03.003
  8. Sakon, J., W. S. Adney, M. E. Himmel, S. R. Thomas, and P. A. Karplus. 1996. Crystal structure of thermostable family 5 endocellulase E1 from Acidothermus cellulolyticus in complex with cellotetraose. Biochemistry 35: 10648-10660 https://doi.org/10.1021/bi9604439
  9. Uegaki, K., M. Shirakawa, T. Fujita, T. Taniguchi, and Y. Kyogoku. 1993. Characterization of the DNA binding domain of the mouse IRF-2 protein. Protein Eng. 6: 195-200 https://doi.org/10.1093/protein/6.2.195
  10. Wilkinson, G. N. 1961. Statistical estimations in enzyme kinetics. Biochem. J. 80: 324-332 https://doi.org/10.1042/bj0800324
  11. Wood, T. M. 1985. Properties of cellulolytic enzyme systems. Biochem. Soc. Trans. 13: 407-410 https://doi.org/10.1042/bst0130407