5LXB image
Entry Detail
PDB ID:
5LXB
Title:
Crystal structure of a mutant binding protein (5HTBP-AChBP) in complex with palonosetron
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2016-09-20
Release Date:
2016-10-12
Method Details:
Experimental Method:
Resolution:
2.34 Å
R-Value Free:
0.24
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Soluble acetylcholine receptor
Chain IDs:A, B, C, D, E, F, G, H, I, J
Chain Length:242
Number of Molecules:10
Biological Source:Aplysia californica
Primary Citation
Palonosetron-5-HT3 Receptor Interactions As Shown by a Binding Protein Cocrystal Structure.
ACS Chem Neurosci 7 1641 1646 (2016)
PMID: 27656911 DOI: 10.1021/acschemneuro.6b00132

Abstact

Palonosetron is a potent 5-HT3 receptor antagonist and an effective therapeutic agent against emesis. Here we identify the molecular determinants of compound recognition in the receptor binding site by obtaining a high resolution structure of palonosetron bound to an engineered acetylcholine binding protein that mimics the 5-HT3 receptor binding site, termed 5-HTBP, and by examining the potency of palonosetron in a range of 5-HT3 receptors with mutated binding site residues. The structural data indicate that palonosetron forms a tight and effective wedge in the binding pocket, made possible by its rigid tricyclic ring structure and its interactions with binding site residues; it adopts a binding pose that is distinct from the related antiemetics granisetron and tropisetron. The functional data show many residues previously shown to interact with agonists and antagonists in the binding site are important for palonosetron binding, and indicate those of particular importance are W183 (a cation-π interaction and a hydrogen bond) and Y153 (a hydrogen bond). This information, and the availability of the structure of palonosetron bound to 5-HTBP, should aid the development of novel and more efficacious drugs that act via 5-HT3 receptors.

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