PDBsum entry: 1ihz

Hydrolase

PDB id: 1ihz

Contents

Protein chain

136 a.a. *

Waters ×95

* Residue conservation analysis

PDB id:

1ihz

Name:

Hydrolase

Title:

Structure of s. Nuclease mutant quintuple mutant v23l/v66l/i72l/i92l/v99l

Structure:

Staphylococcal nuclease. Chain: a. Engineered: yes. Mutation: yes

Source:

Staphylococcus aureus. Organism_taxid: 1280. Strain: foggi. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.65Å R-factor: 0.195 R-free: 0.261

Authors:

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

Key ref:

J.Chen et al. (2004). Proteins with simplified hydrophobic cores compared to other packing mutants. Biophys Chem, 110, 239-248. PubMed id: 15228960 DOI: 10.1016/j.bpc.2004.02.007

Date:

20-Apr-01 Release date: 17-Jun-03

Protein chain

P00644  (NUC_STAAU) -  Thermonuclease

Seq: 231 a.a.

Struc: 136 a.a.*

* PDB and UniProt seqs differ at 5 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.31.1 - Micrococcal nuclease.
• Reaction: Endonucleolytic cleavage to nucleoside 3'-phosphates and 3'-phosphooligonucleotide end-products.

 Gene Ontology (GO) functional annotation 

• Biochemical function: nucleic acid binding (3 terms)

DOI no: 10.1016/j.bpc.2004.02.007

Biophys Chem 110:239-248 (2004)

PubMed id: 15228960

Proteins with simplified hydrophobic cores compared to other packing mutants.

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

ABSTRACT

Efforts to design proteins with greatly reduced sequence diversity have often resulted in proteins with so-called molten globule properties. Substitutions were made at six neighboring sites in the major hydrophobic core of staphylococcal nuclease to create variants with all leucine, all isoleucine or all valine at these sites. The mutant proteins with simplified cores constructed here are quite unstable and have poorly packed cores, attested to by interaction energies. Eight related mutants with greater sequence diversity were also constructed. Comparison to these mutants and 159 other permutations of these 3 aliphatic side chains at these same 6 sites previously constructed shows that the simplified cores are not unusual in their stabilities or interaction energies. Further, crystal structures of the two mutants with the worst packing, as measured by interaction energies, showed no unusual disorder in the core. Therefore, reduction of sequence diversity is not necessarily incompatible with a single stable native structure. Other factors must also contribute to previous protein design failures.