Folding pathway of guanidine-denatured disulfide-intact wild-type and mutant bovine pancreatic ribonuclease A.
The refolding kinetics of guanidine-denatured disulfide-intact bovine pancreatic ribonuclease A (RNase A) and its proline-42-to-alanine mutant (Pro42Ala) have been studied by monitoring tyrosine burial and 2'-cytidine monophosphate (2'CMP) inhibitor binding. The folding rate for wild-type RNase A is faster in the presence of the inhibitor 2'CMP than in its absence, indicating that the transition-state structure in the rate-determining step is stabilized by 2'CMP. The folding rate monitored by 2'CMP binding to the major slow-folding species of Pro42Ala RNase A is faster than the folding rate monitored by tyrosine burial; however, the folding rate monitored by inhibitor binding to the minor slow-folding species is decreased significantly over the folding rate monitored by tyrosine burial, indicating that the major and minor slow-folding species of Pro42Ala fold to the native state with different transition-state conformations in the rate-determining step.
Dodge
R W
RW
Baker Laboratory of Chemistry, Cornell University, Ithaca, New York 14853-1301.
Laity
J H
JH
Rothwarf
D M
DM
Shimotakahara
S
S
Scheraga
H A
HA
D000409:Alanine; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003568:Cytidine Monophosphate / Q000494:pharmacology; D004220:Disulfides; D019791:Guanidine; D006146:Guanidines; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D011392:Proline; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D014443:Tyrosine / Q000032:analysis
D004220:Disulfides; D006146:Guanidines; D011994:Recombinant Proteins; D014443:Tyrosine; D011392:Proline; D012259:Ribonuclease, Pancreatic; D003568:Cytidine Monophosphate; D019791:Guanidine; D000409:Alanine