TY - JOUR
T1 - Identification of functionally important amino acids in the cellulose-binding domain of Trichoderma reesei cellobiohydrolase I
AU - Linder, Markus
AU - Mattinen, Maija-Liisa
AU - Kontteli, Maarit
AU - Lindeberg, Gunnar
AU - Ståhlberg, Jerry
AU - Drakenberg, Torbjörn
AU - Reinikainen, Tapani
AU - Pettersson, Göran
AU - Annila, Arto
PY - 1995
Y1 - 1995
N2 - Cellobiohydrolase I (CBHI) of Trichoderma reesei has two functional domains, a catalytic core domain and a cellulose binding domain (CBD). The structure of the CBD reveals two distinct faces, one of which is flat and the other rough. Several other fungal cellulolytic enzymes have similar two‐domain structures, in which the CBDs show a conserved primary structure. Here we have evaluated the contributions of conserved amino acids in CBHI CBD to its binding to cellulose. Binding isotherms were determined for a set of six synthetic analogues in which conserved amino acids were substituted. Two‐dimensional NMR spectroscopy was used to assess the structural effects of the substitutions by comparing chemical shifts, coupling constants, and NOEs of the backbone protons between the wild‐type CBD and the analogues. In general, the structural effects of the substitutions were minor, although in some cases decreased binding could clearly be ascribed to conformational perturbations. We found that at least two tyrosine residues and a glutamine residue on the flat face were essential for tight binding of the CBD to cellulose. A change on the rough face had only a small effect on the binding and it is unlikely that this face interacts with cellulose directly.
AB - Cellobiohydrolase I (CBHI) of Trichoderma reesei has two functional domains, a catalytic core domain and a cellulose binding domain (CBD). The structure of the CBD reveals two distinct faces, one of which is flat and the other rough. Several other fungal cellulolytic enzymes have similar two‐domain structures, in which the CBDs show a conserved primary structure. Here we have evaluated the contributions of conserved amino acids in CBHI CBD to its binding to cellulose. Binding isotherms were determined for a set of six synthetic analogues in which conserved amino acids were substituted. Two‐dimensional NMR spectroscopy was used to assess the structural effects of the substitutions by comparing chemical shifts, coupling constants, and NOEs of the backbone protons between the wild‐type CBD and the analogues. In general, the structural effects of the substitutions were minor, although in some cases decreased binding could clearly be ascribed to conformational perturbations. We found that at least two tyrosine residues and a glutamine residue on the flat face were essential for tight binding of the CBD to cellulose. A change on the rough face had only a small effect on the binding and it is unlikely that this face interacts with cellulose directly.
U2 - 10.1002/pro.5560040604
DO - 10.1002/pro.5560040604
M3 - Article
SN - 0961-8368
VL - 4
SP - 1056
EP - 1064
JO - Protein Science
JF - Protein Science
IS - 6
ER -