PDBsum entry 5uxt

De novo protein

PDB id: 5uxt

Contents

Protein chains

34 a.a.

30 a.a.

32 a.a.

Ligands

GOL

Waters ×57

PDB id:

5uxt

Name:

De novo protein

Title:

Coiled-coil trimer with glu:trp:lys triad

Structure:

Coiled-coil trimer with glu:trp:lys triad. Chain: a, b, c. Engineered: yes

Source:

Synthetic: yes. Synthetic construct. Organism_taxid: 32630

Resolution:

2.20Å R-factor: 0.202 R-free: 0.275

Authors:

M.S.Smith,W.M.Billings,F.G.Whitby,M.B.Miller,J.L.Price

Key ref:

M.S.Smith et al. (2017). Enhancing a long-range salt bridge with intermediate aromatic and nonpolar amino acids. Org Biomol Chem, 15, 5882-5886. PubMed id: 28678274 DOI: 10.1039/c7ob01198a

Date:

23-Feb-17 Release date: 09-Aug-17

Protein chain

No UniProt id for this chain

Struc: 33 a.a.

Protein chain

No UniProt id for this chain

Struc: 29 a.a.

Protein chain

No UniProt id for this chain

Struc: 31 a.a.

DOI no: 10.1039/c7ob01198a

Org Biomol Chem 15:5882-5886 (2017)

PubMed id: 28678274

Enhancing a long-range salt bridge with intermediate aromatic and nonpolar amino acids.

M.S.Smith, W.M.Billings, F.G.Whitby, M.B.Miller, J.L.Price.

ABSTRACT

The interaction of a positively charged amino acid residue with a negatively charged residue (i.e. a salt bridge) can contribute substantially to protein conformational stability, especially when two ionic groups are in close proximity. At longer distances, this stabilizing effect tends to drop off precipitously. However, several lines of evidence suggest that salt-bridge interaction could persist at longer distances if an aromatic amino acid residue were positioned between the anion and cation. Here we explore this possibility in the context of a peptide in which a Lys residue occupies the i + 8 position relative to an i-position Glu on the solvent-exposed surface of a helix-bundle homotrimer. Variable temperature circular dichroism (CD) experiments indicate that an i + 4-position Trp enables a favorable long-range interaction between Glu and the i + 8 Lys. A substantial portion of this effect relies on the presence of a hydrogen-bond donor on the arene; however, non-polar arenes, a cyclic hydrocarbon, and an acyclic Leu side-chain can also enhance the long-range salt bridge, possibly by excluding water and ions from the space between Glu and Lys.