1b2h

From Proteopedia

Oligo-Peptide Binding Protein Complexed with Lysyl-Ornithyl-Lysine

Structural highlights

1b2h is a 2 chain structure with sequence from Salmonella enterica subsp. enterica serovar Typhimurium. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.9Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

OPPA_SALTY This protein is a component of the oligopeptide permease, a binding protein-dependent transport system, it binds peptides up to five amino acids long with high affinity.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The oligopeptide-binding protein OppA provides a useful model system for studying the physical chemistry underlying noncovalent interactions since it binds a variety of readily synthesized ligands. We have studied the binding of eight closely related tripeptides of the type Lysine-X-Lysine, where X is an abnormal amino acid, by isothermal titration calorimetry (ITC) and X-ray crystallography. The tripeptides fall into three series of ligands, which have been designed to examine the effects of small changes to the central side chain. Three ligands have a primary amine as the second side chain, two have a straight alkane chain, and three have ring systems. The results have revealed a definite preference for the binding of hydrophobic residues over the positively charged side chains, the latter binding only weakly due to unfavorable enthalpic effects. Within the series of positively charged groups, a point of lowest affinity has been identified and this is proposed to arise from unfavorable electrostatic interactions in the pocket, including the disruption of a key salt bridge. Marked entropy-enthalpy compensation is found across the series, and some of the difficulties in designing tightly binding ligands have been highlighted.

Relating structure to thermodynamics: the crystal structures and binding affinity of eight OppA-peptide complexes.,Davies TG, Hubbard RE, Tame JR Protein Sci. 1999 Jul;8(7):1432-44. PMID:10422831^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Davies TG, Hubbard RE, Tame JR. Relating structure to thermodynamics: the crystal structures and binding affinity of eight OppA-peptide complexes. Protein Sci. 1999 Jul;8(7):1432-44. PMID:10422831