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PDBsum entry 1b4h

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Peptide binding protein PDB id
1b4h
Contents
Protein chain
517 a.a. *
Ligands
LYS-DAB-LYS
Metals
_U1 ×8
Waters ×373
* Residue conservation analysis

References listed in PDB file
Key reference
Title Relating structure to thermodynamics: the crystal structures and binding affinity of eight oppa-Peptide complexes.
Authors T.G.Davies, R.E.Hubbard, J.R.Tame.
Ref. Protein Sci, 1999, 8, 1432-1444. [DOI no: 10.1110/ps.8.7.1432]
PubMed id 10422831
Abstract
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.
Secondary reference #1
Title The crystal structures of the oligopeptide-Binding protein oppa complexed with tripeptide and tetrapeptide ligands.
Authors J.R.Tame, E.J.Dodson, G.Murshudov, C.F.Higgins, A.J.Wilkinson.
Ref. Structure, 1995, 3, 1395-1406. [DOI no: 10.1016/S0969-2126(01)00276-3]
PubMed id 8747465
Full text Abstract
Figure 1.
Figure 1. Stereo Cα trace of OppA in the closed, ligand bound form. The tri-lysine ligand is shown in thicker lines. Figure 1. Stereo Cα trace of OppA in the closed, ligand bound form. The tri-lysine ligand is shown in thicker lines.
Figure 5.
Figure 5. . Schematic diagram illustrating the interactions made by the main chain of the tri-lysine ligand with OppA. Protein residues are labelled. Hydrogen bonding and electrostatic interactions are indicated by the dotted lines. R1, R2 and R3 indicate the ligand side chains. Figure 5. . Schematic diagram illustrating the interactions made by the main chain of the tri-lysine ligand with OppA. Protein residues are labelled. Hydrogen bonding and electrostatic interactions are indicated by the dotted lines. R1, R2 and R3 indicate the ligand side chains.
The above figures are reproduced from the cited reference with permission from Cell Press
PROCHECK
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