1BOX

N39S MUTANT OF RNASE SA FROM STREPTOMYCES AUREOFACIENS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.181 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Contribution of a conserved asparagine to the conformational stability of ribonucleases Sa, Ba, and T1.

Hebert, E.J.Giletto, A.Sevcik, J.Urbanikova, L.Wilson, K.S.Dauter, Z.Pace, C.N.

(1998) Biochemistry 37: 16192-16200

  • DOI: 10.1021/bi9815243

  • PubMed Abstract: 
  • The contribution of hydrogen bonding by peptide groups to the conformational stability of globular proteins was studied. One of the conserved residues in the microbial ribonuclease (RNase) family is an asparagine at position 39 in RNase Sa, 44 in RNa ...

    The contribution of hydrogen bonding by peptide groups to the conformational stability of globular proteins was studied. One of the conserved residues in the microbial ribonuclease (RNase) family is an asparagine at position 39 in RNase Sa, 44 in RNase T1, and 58 in RNase Ba (barnase). The amide group of this asparagine is buried and forms two similar intramolecular hydrogen bonds with a neighboring peptide group to anchor a loop on the surface of all three proteins. Thus, it is a good model for the hydrogen bonding of peptide groups. When the conserved asparagine is replaced with alanine, the decrease in the stability of the mutant proteins is 2.2 (Sa), 1.8 (T1), and 2.7 (Ba) kcal/mol. When the conserved asparagine is replaced by aspartate, the stability of the mutant proteins decreases by 1.5 and 1.8 kcal/mol for RNases Sa and T1, respectively, but increases by 0.5 kcal/mol for RNase Ba. When the conserved asparagine was replaced by serine, the stability of the mutant proteins was decreased by 2.3 and 1.7 kcal/mol for RNases Sa and T1, respectively. The structure of the Asn 39 --> Ser mutant of RNase Sa was determined at 1.7 A resolution. There is a significant conformational change near the site of the mutation: (1) the side chain of Ser 39 is oriented differently than that of Asn 39 and forms hydrogen bonds with two conserved water molecules; (2) the peptide bond of Ser 42 changes conformation in the mutant so that the side chain forms three new intramolecular hydrogen bonds with the backbone to replace three hydrogen bonds to water molecules present in the wild-type structure; and (3) the loss of the anchoring hydrogen bonds makes the surface loop more flexible in the mutant than it is in wild-type RNase Sa. The results show that burial and hydrogen bonding of the conserved asparagine make a large contribution to microbial RNase stability and emphasize the importance of structural information in interpreting stability studies of mutant proteins.


    Organizational Affiliation

    Department of Medical Biochemistry, Center for Macromolecular Design, Texas A&M University, College Station 77843-1114, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GUANYL-SPECIFIC RIBONUCLEASE SA
A
96Streptomyces aureofaciensGene Names: rnaSA
EC: 3.1.27.3
Find proteins for P05798 (Streptomyces aureofaciens)
Go to UniProtKB:  P05798
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.218 
  • R-Value Work: 0.181 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 41.490α = 90.00
b = 46.650β = 90.00
c = 51.650γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
AMoREphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-29
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance