Circular dichroism study of ribonuclease A mutants containing the minimal structural requirements for dimerization and swapping.
Four residues Pro19. Leu28, Cys31 and Cys32 proved to be the minimal structural requirements in determining the dimeric structure and the N-terminal segment swapping of bovine seminal ribonuclease, BS-RNase. We analyzed the content of secondary and tertiary structures in RNase A, P-RNase A, PL-RNase A, MCAM-PLCC-RNase A and MCAM-BS-RNase, performing near and far-UV CD spectra. It results that the five proteins have very similar native conformations. Thermal denaturation at pH 5.0 of the proteins. studied by means of CD measurements. proved reversible and well represented by the two-state N<==>D transition model. Thermodynamic data are discussed in the light of the structural information available for RNase A and BS-RNase.
Catanzano
F
F
Dipartimento di Chimica, Università di Napoli Federico II, Italy.
Graziano
G
G
Cafaro
V
V
D'Alessio
G
G
Di Donato
A
A
Barone
G
G
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D019281:Dimerization; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D013816:Thermodynamics
D012259:Ribonuclease, Pancreatic