1EZ8

STRUCTURE OF S. NUCLEASE STABILIZING MUTANT T33V

PDB DOI: 10.2210/pdb1EZ8/pdb

Classification: HYDROLASE
Organism(s): Staphylococcus aureus
Expression System: Escherichia coli
Mutation(s): Yes

Deposited: 2000-05-10 Released: 2000-10-18
Deposition Author(s): Chen, J., Lu, Z., Sakon, J., Stites, W.E.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 1.85 Å
R-Value Free: 0.265

wwPDB Validation 3D Report Full Report

This is version 1.3 of the entry. See complete history.

Literature

Increasing the thermostability of staphylococcal nuclease: implications for the origin of protein thermostability.

Chen, J., Lu, Z., Sakon, J., Stites, W.E.

(2000) J Mol Biol 303: 125-130

PubMed: 11023780 Search on PubMed
DOI: 10.1006/jmbi.2000.4140
Primary Citation of Related Structures:
1EY0, 1EY4, 1EY5, 1EY6, 1EY7, 1EY8, 1EY9, 1EYA, 1EYC, 1EYD, 1EZ6, 1EZ8

PubMed Abstract:

Seven hyper-stable multiple mutants have been constructed in staphylococcal nuclease by various combinations of eight different stabilizing single mutants. The stabilities of these multiple mutants determined by guanidine hydrochloride denaturation were 3.4 to 5.6 kcal/mol higher than that of the wild-type. Their thermal denaturation midpoint temperatures were 12.6 to 22.9 deg. C higher than that of the wild-type. These are among the greatest increases in protein stability and thermal denaturation midpoint temperature relative to the wild-type yet attained. There has been great interest in understanding how proteins found in thermophilic organisms are stabilized. One frequently cited theory is that the packing of hydrophobic side-chains is improved in the cores of proteins isolated from thermophiles when compared to proteins from mesophiles. The crystal structures of four single and five multiple stabilizing mutants of staphylococcal nuclease were solved to high resolution. No large overall structural change was found, with most changes localized around the sites of mutation. Rearrangements were observed in the packing of side-chains in the major hydrophobic core, although none of the mutations was in the core. It is surprising that detailed structural analysis showed that packing had improved, with the volume of the mutant protein's hydrophobic cores decreasing as protein stability increased. Further, the number of van der Waals interactions in the entire protein showed an experimentally significant increase correlated with increasing stability. These results indicate that optimization of packing follows as a natural consequence of increased protein thermostability and that good packing is not necessarily the proximate cause of high stability. Another popular theory is that thermostable proteins have more electrostatic and hydrogen bonding interactions and these are responsible for the high stabilities. The mutants here show that increased numbers of electrostatic and hydrogen bonding interactions are not obligatory for large increases in protein stability.

Organizational Affiliation:

Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701-1201, USA.

Macromolecules

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(by identity cutoff) | 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
STAPHYLOCOCCAL NUCLEASE	A	149	Staphylococcus aureus	Mutation(s): 1 Gene Names: nuc EC: 3.1.31.1
UniProt
Find proteins for P00644 (Staphylococcus aureus) Explore P00644 Go to UniProtKB: P00644
Entity Groups
Sequence Clusters	30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt Group	P00644
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Reference Sequence