8JXZ

Chitin binding SusD-like protein AqSusD in complex with (GlcNAc)3

Summary for 8JXZ

• Entry DOI: 10.2210/pdb8jxz/pdb
• Related PRD ID: PRD_900017
• Descriptor: SusD-like protein AqSusD, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total)
• Functional Keywords: susd-like protein, sugar binding protein
• Biological source: Aquimarina
• Total number of polymer chains: 1
• Total formula weight: 58794.59

Authors

Yang, J. (deposition date: 2023-07-01, release date: 2023-11-01, Last modification date: 2024-02-28)

Primary citation

Yang, J.,Zhang, L.,Lin, S.,Li, W.,Liu, C.,Yan, J.,Li, S.,Long, L.
Structural insights of a SusD-like protein in marine Bacteroidetes bacteria reveal the molecular basis for chitin recognition and acquisition.
Febs J., 291:584-595, 2024

PubMed Abstract: Efficient recognition and transportation of chitin oligosaccharides are crucial steps for the utilization of chitin by heterotrophic bacteria. In this study, we employed structural biological and biochemical approaches to investigate the substrate recognition and acquisition mechanism of a novel chitin-binding SusD-like protein, AqSusD, which is derived from the chitin utilization gene cluster of a marine Bacteroides strain (Aquimarina sp. SCSIO 21287). We resolved the crystal structures of the AqSusD apo-protein and its complex with chitin oligosaccharides. Our results revealed that some crucial residues (Gln67, Phe87, and Asp276) underwent significant conformational changes to form tighter substrate binding sites for ligand binding. Moreover, we identified the functions of key amino acid residues and discovered that π-π stacking and hydrogen bonding between AqSusD and the ligand played significant roles in recognition of the protein for chitin oligosaccharide binding. Based on our findings and previous investigations, we put forward a model for the mechanism of chitin oligosaccharide recognition, capture, and transport by AqSusD, in collaboration with the membrane protein AqSusC. Our study deepens the understanding of the molecular-level "selfish" use of polysaccharides such as chitin by Bacteroides.

PubMed: 37845429
DOI: 10.1111/febs.16974

Experimental method

X-RAY DIFFRACTION (2.2 Å)