Conservation of Flexible Residue Clusters among Structural and Functional Enzyme Homologues

Gagne, Donald; Charest, Laurie-Anne; Morin, Sebastien; Kovrigin, Evgenii L. et Doucet, Nicolas ORCID: https://orcid.org/0000-0002-1952-9380 (2012). Conservation of Flexible Residue Clusters among Structural and Functional Enzyme Homologues Journal of Biological Chemistry , vol. 287 , nº 53. pp. 44289-44300. DOI: 10.1074/jbc.M112.394866.

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Résumé

Conformational flexibility between structural ensembles is an essential component of enzyme function. Although the broad dynamical landscape of proteins is known to promote a no. 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 biol. 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 anal., and ligand titrn. expts. to successfully capture and compare the role of conformational flexibility between two structural homologues of the pancreatic RNase family: RNase A and eosinophil cationic protein (or RNase 3). In addn. 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. [on SciFinder(R)]

Type de document:	Article
Mots-clés libres:	Mutagenesis; NMR; Protein Conformation; Protein Dynamics; Ribonuclease
Centre:	Centre INRS-Institut Armand Frappier
Date de dépôt:	07 mars 2024 20:01
Dernière modification:	07 mars 2024 20:01
URI:	https://espace.inrs.ca/id/eprint/14027

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