4CL1 image
Deposition Date 2014-01-10
Release Date 2014-04-02
Last Version Date 2024-11-20
Entry Detail
PDB ID:
4CL1
Keywords:
Title:
The crystal structure of NS5A domain 1 from genotype 1a reveals new clues to the mechanism of action for dimeric HCV inhibitors
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
3.50 Å
R-Value Free:
0.26
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:NON-STRUCTURAL PROTEIN 5A
Chain IDs:A, B, C, D
Chain Length:177
Number of Molecules:4
Biological Source:HEPATITIS C VIRUS (ISOLATE H77)
Primary Citation
The Crystal Structure of Ns5A Domain 1 from Genotype 1A Reveals New Clues to the Mechanism of Action for Dimeric Hcv Inhibitors.
Protein Sci. 23 723 ? (2014)
PMID: 24639329 DOI: 10.1002/PRO.2456

Abstact

New direct acting antivirals (DAAs) such as daclatasvir (DCV; BMS-790052), which target NS5A function with picomolar potency, are showing promise in clinical trials. The exact nature of how these compounds have an inhibitory effect on HCV is unknown; however, major resistance mutations appear in the N-terminal region of NS5A that include the amphipathic helix and domain 1. The dimeric symmetry of these compounds suggests that they act on a dimer of NS5A, which is also consistent with the presence of dimers in crystals of NS5A domain 1 from genotype 1b. Genotype 1a HCV is less potently affected by these compounds and resistance mutations have a greater effect than in the 1b genotypes. We have obtained crystals of domain 1 of the important 1a NS5A homologue and intriguingly, our X-ray crystal structure reveals two new dimeric forms of this domain. Furthermore, the high solvent content (75%) makes it ideal for ligand-soaking. Daclatasvir (DCV) shows twofold symmetry suggesting NS5A dimers may be of physiological importance and serve as potential binding sites for DCV. These dimers also allow for new conformations of a NS5A expansive network which could explain its operation on the membranous web. Additionally, sulfates bound in the crystal structure may provide evidence for the previously proposed RNA binding groove, or explain regulation of NS5A domain 2 and 3 function and phosphorylation, by domain 1.

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