The crystal structure of CbpD clarifies substrate‐specificity motifs in chitin‐active lytic polysaccharide monooxygenases. Issue 8 (27th July 2022)

• Record Type: Journal Article
• Authors: Dade, Christopher M.; Douzi, Badreddine; Cambillau, Christian; Ball, Genevieve; Voulhoux, Romé; Forest, Katrina T.
• Is Part Of: Acta crystallographica. Volume 78:Issue 8(2022)
• Page Start: 1064
• Page End: 1078
• Publication Date: 2022-07-27
• Subjects: LPMOs -- lytic polysaccharide monooxygenases -- AA10 -- Pseudomonas aeruginosa -- chitin binding protein CbpD -- type 2 secretion systems -- RoseTTAFold -- biofuels -- bacterial pathogenesis; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; Molecular biology -- Periodicals; Molecular structure -- Periodicals; Biomolecules -- Structure -- Periodicals; Cytology -- Periodicals; Biomolecules -- Structure; Crystallography; Cytology; Molecular biology; Molecular structure; X-ray crystallography; Periodicals; 548
• DOI: 10.1107/S2059798322007033
• Languages: English
• ISSNs: 2059-7983

Abstract

Abstract : The 3 Å resolution crystal structure of the Pseudomonas aeruginosa virulence factor CbpD both supports and challenges the current model of how lytic polysaccharide monooxygenases bind chitin and raises interesting possibilities about how type 2 secretion‐system substrates may interact with the secretion machinery. This structure also demonstrates the utility of new, AI‐powered, protein structure‐prediction algorithms in making challenging structural targets tractable. Abstract : Pseudomonas aeruginosa secretes diverse proteins via its type 2 secretion system, including a 39 kDa chitin‐binding protein, CbpD. CbpD has recently been shown to be a lytic polysaccharide monooxygenase active on chitin and to contribute substantially to virulence. To date, no structure of this virulence factor has been reported. Its first two domains are homologous to those found in the crystal structure of Vibrio cholerae GbpA, while the third domain is homologous to the NMR structure of the CBM73 domain of Cellvibrio japonicus Cj LPMO10A. Here, the 3.0 Å resolution crystal structure of CbpD solved by molecular replacement is reported, which required ab initio models of each CbpD domain generated by the artificial intelligence deep‐learning structure‐prediction algorithm RoseTTAFold . The structure of CbpD confirms some previously reported substrate‐specificity motifs among LPMOAA10s, while challenging the predictive power of others. Additionally, the structure of CbpD shows that post‐translational modifications occur on the chitin‐binding surface. Moreover, the structure raises interesting possibilities about how type 2 secretion‐system substrates may interact with the secretion machinery and demonstrates the utility of new artificial intelligence protein structure‐prediction algorithms in making challenging structural targets tractable.