title: Joint X-ray crystallographic and molecular dynamics study of cellobiohydrolase I from Trichoderma harzianum: deciphering the structural features of cellobiohydrolase catalytic activity.
abstract: Aiming to contribute toward the characterization of new, biotechnologically relevant cellulolytic enzymes, we report here the first crystal structure of the catalytic core domain of Cel7A (cellobiohydrolase I) from the filamentous fungus Trichoderma harzianum IOC 3844. Our structural studies and molecular dynamics simulations show that the flexibility of Tyr260, in comparison with Tyr247 from the homologous Trichoderma reesei Cel7A, is enhanced as a result of the short side-chains of adjacent Val216 and Ala384 residues and creates an additional gap at the side face of the catalytic tunnel. T. harzianum cellobiohydrolase I also has a shortened loop at the entrance of the cellulose-binding tunnel, which has been described to interact with the substrate in T. reesei Cel7A. These structural features might explain why T. harzianum Cel7A displays higher k(cat) and K(m) values, and lower product inhibition on both glucoside and lactoside substrates, compared with T. reesei Cel7A.
authors.affiliation: Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
authors.forename: Larissa C
authors.initials: LC
authors.lastname: Textor
authors.forename: Francieli
authors.initials: F
authors.lastname: Colussi
authors.forename: Rodrigo L
authors.initials: RL
authors.lastname: Silveira
authors.forename: Viviane
authors.initials: V
authors.lastname: Serpa
authors.forename: Bruno L
authors.initials: BL
authors.lastname: de Mello
authors.forename: João Renato C
authors.initials: JR
authors.lastname: Muniz
authors.forename: Fabio M
authors.initials: FM
authors.lastname: Squina
authors.forename: Nei
authors.initials: N
authors.lastname: Pereira
authors.forename: Munir S
authors.initials: MS
authors.lastname: Skaf
authors.forename: Igor
authors.initials: I
authors.lastname: Polikarpov
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D043366:Cellulose 1,4-beta-Cellobiosidase