9wsf

Crystal structure of Sigma28/FlgM complex from Pseudomonas aeruginosa at 1.95 Angstrom resolution

spinqualitylabelsall models 9wsf, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9wsf is a 2 chain structure with sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.95Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Late flagellar genes in Pseudomonas aeruginosa are transcribed by the group 3 sigma factor, FliA (sigma28). sigma28 drives the expression of flagellin, which assembles into the flagellar filament in this monoflagellated bacterium. This function is suppressed by the anti-sigma factor FlgM. Here, we present the 1.95A resolution crystal structure of sigma28-FlgM complex, along with a 3.4A structure of sigma28RNAP open promoter complex determined using single particle cryo-electron microscopy from P. aeruginosa. The sigma28 adopts a compact conformation upon binding to the anti-sigma factor FlgM, which contacts all three domains of the sigma factor. This conformation is neither conducive to interactions with RNA polymerase nor the promoter DNA. The cryo-EM structure reveals base-specific interactions of sigma28 domain 4 (sigma4) with -35 element, flipping of -11 base of the template strand, novel interactions of template strand with domain 2 (sigma2) and 3 (sigma3), and partial insertion of sigma finger into the active site cleft, offering unique features of group 3 sigma interactions with promoter DNA. Perturbation of key residues affects transcription in vitro and flagellar phenotypes as well as bacterial motility in vivo. Analysis of the structural data presented here reveals new insights into transcription regulation of late flagellar genes. Structural insights into sigma28-dependent transcription initiation and its regulation by anti-sigma factor in Pseudomonas aeruginosa.,Sheenu, Kumar V, Sahoo PK, Kandiah E, Jain D Nucleic Acids Res. 2026 Jan 5;54(1):gkaf1414. doi: 10.1093/nar/gkaf1414. PMID:41521663 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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