High temperatures enhance cooperative motions between CBM and catalytic domains of a thermostable cellulase: mechanism insights from essential dynamics

Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil.
Physical Chemistry Chemical Physics (Impact Factor: 4.2). 06/2011; 13(30):13709-20. DOI: 10.1039/c0cp02697b
Source: PubMed

ABSTRACT Cellulases from thermophiles are capable of cleaving sugar chains from cellulose efficiently at high temperatures. The thermo-resistant Cel9A-68 cellulase possesses two important domains: CBM and a catalytic domain connected by a Pro/Ser/Thr rich linker. These domains act cooperatively to allow efficient catalysis. Despite exhaustive efforts to characterize cellulase binding and mechanism of action, a detailed description of the cellulose intrinsic flexibility is still lacking. From computational simulations we studied the temperature influence on the enzyme plasticity, prior to substrate binding. Interestingly, we observed an enhancement of collective motions at high temperatures. These motions are the most representative and describe an intrinsic hinge bending transition. A detailed analysis of these motions revealed an interdomain approximation where D459 and G460, located at the linker region, are the hinge residues. Therefore, we propose a new putative site for mutagenesis targeting the modulation of such conformational transition that may be crucial for activity.

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Available from: Paulo Ricardo Batista, Jul 15, 2015
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    • "Cellulase enzymes belong to different families of glycoside hydrolases (GHs). Many cellulases contain a catalytic domain (CD) and a cellulose binding domain or module (Linder and Teeri, 1997); these are connected by a Pro/Ser/Thr rich linker (Batista et al., 2011). Other domains may also be present and these were recently described for bacterial cellulases in a comprehensive genome analysis (Medie et al., 2012). "
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