Structural basis for diguanylate cyclase activation by its binding partner in Pseudomonas aeruginosa

• Published in: eLife 2021-09, Vol.10
• Main Authors: Chen, Gukui, Zhou, Jiashen, Zuo, Yili, Huo, Weiping, Peng, Juan, Li, Meng, Zhang, Yani, Wang, Tietao, Zhang, Lin, Zhang, Liang, Liang, Haihua
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Binding Sites; Biofilms; Biofilms - growth & development; Catalysis; Cell cycle; Chronic infection; Crystal structure; Crystals; Dinucleoside Phosphates - chemistry; Dinucleoside Phosphates - metabolism; Enzyme Activation; Enzymes; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Health aspects; Kinases; Microbiology and Infectious Disease; Mutagenesis; Phosphorus-Oxygen Lyases - chemistry; Phosphorus-Oxygen Lyases - genetics; Phosphorus-Oxygen Lyases - metabolism; Phosphorylation; Plasmids; Protein Binding; Protein Conformation; Proteins; Pseudomonas aeruginosa; Pseudomonas aeruginosa - enzymology; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - growth & development; SiaC; SiaD; Signal Transduction; Structural Biology and Molecular Biophysics; Structure; Structure-Activity Relationship
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.67289

Cyclic-di-guanosine monophosphate (c-di-GMP) is an important effector associated with acute-chronic infection transition in . Previously, we reported a signaling network SiaABCD, which regulates biofilm formation by modulating c-di-GMP level. However, the mechanism for SiaD activation by SiaC remains elusive. Here we determine the crystal structure of SiaC-SiaD-GpCpp complex and revealed a unique mirror symmetric conformation: two SiaD form a dimer with long stalk domains, while four SiaC bind to the conserved motifs on the stalks of SiaD and stabilize the conformation for further enzymatic catalysis. Furthermore, SiaD alone exhibits an inactive pentamer conformation in solution, demonstrating that SiaC activates SiaD through a dynamic mechanism of promoting the formation of active SiaD dimers. Mutagenesis assay confirmed that the stalks of SiaD are necessary for its activation. Together, we reveal a novel mechanism for DGC activation, which clarifies the regulatory networks of c-di-GMP signaling.