Structural basis for chitin acquisition by marine Vibrio species

Anuwat Aunkham, Michael Zahn, Anusha Kesireddy, Karunakar Reddy Pothula, Albert Schulte, Arnaud Baslé, Ulrich Kleinekathöfer, Wipa Suginta, Bert van den Berg

Research output: Contribution to journalArticlepeer-review

48 Downloads (Pure)

Abstract

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.
Original languageEnglish
Article number220
Number of pages13
JournalNature Communications
Volume9
Issue number1
Early online date15 Jan 2018
DOIs
Publication statusPublished - 1 Dec 2018

Fingerprint

Dive into the research topics of 'Structural basis for chitin acquisition by marine <i>Vibrio </i>species'. Together they form a unique fingerprint.

Cite this