Valine 108, a chain-folding initiation site-belonging residue, crucial for the ribonuclease A stability.
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.
Coll
M G
MG
Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus Montilivi, Girona, 17071, Spain.
Protasevich
I I
II
Torrent
J
J
Ribó
M
M
Lobachov
V M
VM
Makarov
A A
AA
Vilanova
M
M
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
D011994:Recombinant Proteins; D012259:Ribonuclease, Pancreatic; D014633:Valine