Correlation of temperature induced conformation change with optimum catalytic activity in the recombinant G/11 xylanase A from Bacillus subtilis strain 168 (1A1)

• Autor(a) principal: Murakami, M. T.
• Data de Publicação: 2005
• Outros Autores: Arni, R. K., Vieira, D. S., Degreve, L., Ruller, R., Ward, R. J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.febslet.2005.10.039; http://hdl.handle.net/11449/21972
• topic: thermostable enzyme; Crystal structure; molecular dynamics

The 1.7 angstrom resolution crystal structure of recombinant family G/11 beta-1,4-xylanase (rXynA) from Bacillus subtilis 1A1 shows a jellyroll fold in which two curved P-sheets form the active-site and substrate-binding cleft. The onset of thermal denaturation of rXynA occurs at 328 K, in excellent agreement with the optimum catalytic temperature. Molecular dynamics simulations at temperatures of 298-328 K demonstrate that below the optimum temperature the thumb loop and palm domain adopt a closed conformation. However, at 328 K these two domains separate facilitating substrate access to the active-site pocket, thereby accounting for the optimum catalytic temperature of the rXynA. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.