Molecular simulations provide new insights into the role of the accessory immunoglobulin-like domain of Cel9A.
Cel9A from the thermoacidophilic bacterium Alicyclobacillus acidocaldarius belongs to the subfamily E1 of family 9 glycoside hydrolases, many members of which have an N-terminal Ig-like domain followed by the catalytic domain. The Ig-like domain is not directly involved in either carbohydrate binding or biocatalysis; however, deletion of the Ig-domain promotes loss of enzymatic activity. We have investigated the functional role of the Ig-like domain using molecular dynamics simulations. Our simulations indicate that residues within the Ig-like domain are dynamically correlated with residues in the carbohydrate-binding pocket and with key catalytic residues of Cel9A. Free energy perturbation simulations indicate that the Ig-like domain stabilizes the catalytic domain and may be responsible for the enhanced thermostability of Cel9A.
Liu
Hanbin
H
Deconstruction Division, Joint BioEnergy Institute, Emeryville, CA, United States.
Pereira
Jose Henrique
JH
Adams
Paul D
PD
Sapra
Rajat
R
Simmons
Blake A
BA
Sale
Kenneth L
KL
D056450:Alicyclobacillus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D018360:Crystallography, X-Ray; D006868:Hydrolysis; D007136:Immunoglobulins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
D001426:Bacterial Proteins; D007136:Immunoglobulins; D050505:Mutant Proteins