Skip to Content
MilliporeSigma
  • Conservation of flexible residue clusters among structural and functional enzyme homologues.

Conservation of flexible residue clusters among structural and functional enzyme homologues.

The Journal of biological chemistry (2012-11-09)
Donald Gagné, Laurie-Anne Charest, Sébastien Morin, Evgenii L Kovrigin, Nicolas Doucet
ABSTRACT

Conformational flexibility between structural ensembles is an essential component of enzyme function. Although the broad dynamical landscape of proteins is known to promote a number of functional events on multiple time scales, it is yet unknown whether structural and functional enzyme homologues rely on the same concerted residue motions to perform their catalytic function. It is hypothesized that networks of contiguous and flexible residue motions occurring on the biologically relevant millisecond time scale evolved to promote and/or preserve optimal enzyme catalysis. In this study, we use a combination of NMR relaxation dispersion, model-free analysis, and ligand titration experiments to successfully capture and compare the role of conformational flexibility between two structural homologues of the pancreatic ribonuclease family: RNase A and eosinophil cationic protein (or RNase 3). In addition to conserving the same catalytic residues and structural fold, both homologues show similar yet functionally distinct clusters of millisecond dynamics, suggesting that conformational flexibility can be conserved among analogous protein folds displaying low sequence identity. Our work shows that the reduced conformational flexibility of eosinophil cationic protein can be dynamically and functionally reproduced in the RNase A scaffold upon creation of a chimeric hybrid between the two proteins. These results support the hypothesis that conformational flexibility is partly required for catalytic function in homologous enzyme folds, further highlighting the importance of dynamic residue sectors in the structural organization of proteins.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ribonuclease B from bovine pancreas, BioReagent, ≥50 Kunitz units/mg protein, ≥80% (SDS-PAGE)
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type I-AS, 50-100 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, (Solution of 50% glycerol, 10mM Tris-HCL pH 8.0)
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type II-A, ≥60% (SDS-PAGE), >= 60 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, for molecular biology, ≥70 Kunitz units/mg protein, lyophilized
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type XII-A, ≥90% (SDS-PAGE), 75-125 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type I-A, powder, ≥60% RNase A basis (SDS-PAGE), ≥50 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type X-A, ≥90% (SDS-PAGE), ≥70 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, Type III-A, ≥85% RNase A basis (SDS-PAGE), 85-140 Kunitz units/mg protein
Sigma-Aldrich
Ribonuclease A from bovine pancreas, 4×cryst., ~70 U/mg (acc. to Kunitz)