Buried, charged, non-ion-paired aspartic acid 76 contributes favorably to the conformational stability of ribonuclease T1.


Abstract

The side-chain carboxyl of Asp 76 in ribonuclease T1 (RNase T1) is buried, charged, non-ion-paired, and forms three good intramolecular hydrogen bonds (2.63, 2.69, and 2.89 A) and a 2.66 A hydrogen bond to a buried, conserved water molecule. When Asp 76 was replaced by Asn, Ser, and Ala, the conformational stability of the protein decreased by 3.1, 3.2, and 3.7 kcal/mol, respectively. The stability was measured as a function of pH for wild-type RNase T1 and the D76N mutant and showed that the pH dependence below pH 3 was almost entirely due to Asp 76. The pK of Asp 76 is 0.5 in the native state and 3.7 in the denatured state. Thus, the hydrogen bonding of the carboxyl group of Asp 76 contributes more than half of the net stability of RNase T1 at pH 7. In addition, the charged carboxyl of Asp 76 stabilizes structure in the denatured states of RNase T1 that is not present in D76N, D76S, and D76A. Study holds ProTherm entries: 5713, 5714, 5715, 5716, 5717, 5718, 5719, 5720, 5721, 5722, 5723, 5724, 5725, 5726, 5727, 5728, 5729, 5730, 14289, 14290, 14291 Extra Details: charged; non-ion-paired; intramolecular hydrogen bond;,conformational stability

Submission Details

ID: RLZ9R3mu3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:30 p.m.

Version: 1

Publication Details
Giletto A;Pace CN,Biochemistry (1999) Buried, charged, non-ion-paired aspartic acid 76 contributes favorably to the conformational stability of ribonuclease T1. PMID:10529213
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