5MDS image
Deposition Date 2016-11-13
Release Date 2017-12-20
Last Version Date 2024-01-17
Entry Detail
PDB ID:
5MDS
Title:
Crystal structure of outer membrane expressed Chitoporin VhChip from Vibrio harveyi in complex with chitotetraose
Biological Source:
Source Organism:
Vibrio harveyi (Taxon ID: 669)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.60 Å
R-Value Free:
0.24
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Chitoporin
Gene (Uniprot):chiP
Chain IDs:A, B, C
Chain Length:350
Number of Molecules:3
Biological Source:Vibrio harveyi
Ligand Molecules
Primary Citation
Structural basis for chitin acquisition by marine Vibrio species.
Nat Commun 9 220 220 (2018)
PMID: 29335469 DOI: 10.1038/s41467-017-02523-y

Abstact

Chitin, an insoluble polymer of N-acetylglucosamine, is one of the most abundant biopolymers on Earth. By degrading chitin, chitinolytic bacteria such as Vibrio harveyi are critical for chitin recycling and maintenance of carbon and nitrogen cycles in the world's oceans. A decisive step in chitin degradation is the uptake of chito-oligosaccharides by an outer membrane protein channel named chitoporin (ChiP). Here, we report X-ray crystal structures of ChiP from V. harveyi in the presence and absence of chito-oligosaccharides. Structures without bound sugar reveal a trimeric assembly with an unprecedented closing of the transport pore by the N-terminus of a neighboring subunit. Substrate binding ejects the pore plug to open the transport channel. Together with molecular dynamics simulations, electrophysiology and in vitro transport assays our data provide an explanation for the exceptional affinity of ChiP for chito-oligosaccharides and point to an important role of the N-terminal gate in substrate transport.

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Primary Citation of related structures