title: Valine 108, a chain-folding initiation site-belonging residue, crucial for the ribonuclease A stability.
abstract: Thermal denaturation of bovine pancreatic ribonuclease A and a set of its single variants, carrying replacements of hydrophobic residues in the postulated 106-118 chain folding initiation site, has been studied by differential scanning calorimetry. Ribonuclease A variants undergo a two-state thermal transition denaturation except for those with replacement of valine 108. Most mutations cause a significant destabilization of the protein compared to the wild-type, thus demonstrating the importance of hydrophobic residues at the 106-118 region in maintaining the stability of the molecule. Among them, those of valine 108 promote the greatest (14-27 degrees C) destabilization of the molecule. Therefore, valine 108 plays a crucial role for ribonuclease A stability.
authors.affiliation: Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus Montilivi, Girona, 17071, Spain.
authors.forename: M G
authors.initials: MG
authors.lastname: Coll
authors.forename: I I
authors.initials: II
authors.lastname: Protasevich
authors.forename: J
authors.initials: J
authors.lastname: Torrent
authors.forename: M
authors.initials: M
authors.lastname: Ribó
authors.forename: V M
authors.initials: VM
authors.lastname: Lobachov
authors.forename: A A
authors.initials: AA
authors.lastname: Makarov
authors.forename: M
authors.initials: M
authors.lastname: Vilanova
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002942:Circular Dichroism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D066298:In Vitro Techniques; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010179:Pancreas / Q000201:enzymology; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics; D014633:Valine / Q000737:chemistry
chemical_list: D011994:Recombinant Proteins; D012259:Ribonuclease, Pancreatic; D014633:Valine