The paradox between m values and deltaCp's for denaturation of ribonuclease T1 with disulfide bonds intact and broken.


Abstract

Urea-induced denaturations of RNase T1 and reduced and carboxyamidated RNase T1 (RTCAM) as a function of temperature were analyzed using the linear extrapolation method, and denaturation m values, deltaCp, deltaH, deltaS, and deltaG quantities were determined. Because both deltaCp and m values are believed to reflect the protein surface area newly exposed on denaturation, the prediction is that the ratio of m values for RNase T1 and RTCAM should equal the deltaCp ratio for the two proteins. This is not the case, for it is found that the m value of RTCAM is 1.5 times that of RNase T1, while the denaturation deltaCp's for the two proteins are identical. The paradox of why the two parameters, m and deltaCp, are not equivalent in their behavior is of importance in the interpretations of their respective molecular-level meanings. It is found that the measured denaturation deltaCp's are consistent with deltaCp's calculated on the basis of empirical relationships between the change in surface area on denaturation (deltaASA), and that the measured m value of RNase T1 agrees with m calculated from empirical data relating m to deltaASA. However, the measured m of RTCAM is so much out of line with its calculated m as to call into question the validity of always equating m with surface area newly exposed on denaturation. Study holds ProTherm entries: 6756, 6757, 6758, 6759, 6760 Extra Details: additive : EDTA(2 mM),

Submission Details

ID: rqyESLrd

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:32 p.m.

Version: 1

Publication Details
Baskakov IV;Bolen DW,Protein Sci. (1999) The paradox between m values and deltaCp's for denaturation of ribonuclease T1 with disulfide bonds intact and broken. PMID:10386881
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1B2M 1998-11-27T00:00:00+0000 2.0 THREE-DIMENSIONAL STRUCTURE OF RIBONULCEASE T1 COMPLEXED WITH AN ISOSTERIC PHOSPHONATE ANALOGUE OF GPU: ALTERNATE SUBSTRATE BINDING MODES AND CATALYSIS.
1BIR 1996-01-04T00:00:00+0000 1.8 RIBONUCLEASE T1, PHE 100 TO ALA MUTANT COMPLEXED WITH 2' GMP
1BU4 1998-09-11T00:00:00+0000 1.9 RIBONUCLEASE 1 COMPLEX WITH 2'GMP
1BVI 1998-09-15T00:00:00+0000 1.9 RIBONUCLEASE T1 (WILDTYPE) COMPLEXED WITH 2'GMP
1CH0 1999-03-30T00:00:00+0000 2.3 RNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENT
1DET 1996-02-20T00:00:00+0000 1.8 RIBONUCLEASE T1 CARBOXYMETHYLATED AT GLU 58 IN COMPLEX WITH 2'GMP
1FYS 2000-10-03T00:00:00+0000 2.0 Ribonuclease T1 V16C mutant
1FZU 2000-10-04T00:00:00+0000 1.8 RNAse T1 V78A mutant
1G02 2000-10-05T00:00:00+0000 1.86 Ribonuclease T1 V16S mutant
1GSP 1997-11-28T00:00:00+0000 2.2 RIBONUCLEASE T1 COMPLEXED WITH 2',3'-CGPS, 1 DAY

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Guanyl-specific ribonuclease T1 P00651 RNT1_ASPOR