Structural organization and assembly of flagellar hook protein from Salmonella typhimurium.


The terminal regions of monomeric hook protein from Salmonella typhimurium are known to be highly mobile and exposed to the solvent. Although hook protein exhibits an unusual far-UV circular dichroism spectrum, resembling that of random coil structures, our calorimetric experiments clearly demonstrate that the molecule has a compact ordered core. The compact part probably consists of three domains as suggested by deconvolution analysis of the calorimetric melting profiles. Secondary structure prediction, together with the analysis of far-UV circular dichroism spectra, has shown that the domains of monomeric hook protein contain beta-sheeted structures without significant alpha-helical content. The polymerization of hook protein is accompanied by the stabilization of its disordered terminal regions into a predominantly alpha-helical domain. Evaluation of circular dichroism data suggests that about 45 terminal residues are involved in helical segments. Coiled-coil prediction indicates that whereas the whole carboxy-terminal helical region of hook protein has a strong bundle-forming potential, there is only a single short amino-terminal segment exhibiting weak coiled-coil forming tendencies. The formation of alpha-helical bundles is commonly believed to be a key event during the polymerization of the axial structure of bacterial flagella. To clarify the role of helical bundle formation in hook assembly, proteolytic fragments of hook protein with truncations of various lengths in their carboxy-terminal disordered regions were generated, and their polymerization behavior was investigated. We found that even fragments completely lacking the main helix-forming carboxy-terminal regions can polymerize into filaments in vitro under appropriately high salt concentrations. Our results suggest that, although helical bundle formation may occur during self-assembly, governing precise subunit packing and playing an important role in the stabilization of hook filaments, it is not the principal interaction mainly responsible for the development of their filamentous structure. Study holds ProTherm entries: 2959 Extra Details: bacterial flagellum; hook protein; domain structure;,secondary structure; coiled-coil formation

Submission Details

ID: rBEbhuwy3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:20 p.m.

Version: 1

Publication Details
Vonderviszt F;Závodszky P;Ishimura M;Uedaira H;Namba K,J. Mol. Biol. (1995) Structural organization and assembly of flagellar hook protein from Salmonella typhimurium. PMID:7658470
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
6KFK 2019-07-08T00:00:00+0000 4.1 Structure of Salmonella flagellar hook reveals intermolecular domain interactions for the universal joint function
7E80 2021-02-28T00:00:00+0000 3.67 Cryo-EM structure of the flagellar rod with hook and export apparatus from Salmonella
7E82 2021-02-28T00:00:00+0000 3.3 Cryo-EM structure of the flagellar rod with partial hook from Salmonella
7CBM 2020-06-12T00:00:00+0000 3.2 Cryo-EM structure of the flagellar distal rod with partial hook from Salmonella
6K9Q 2019-06-17T00:00:00+0000 3.1 Structure of the native supercoiled hook as a universal joint
7CGB 2020-07-01T00:00:00+0000 3.4 Cryo-EM structure of the flagellar hook from Salmonella
3A69 2009-08-26T00:00:00+0000 7.1 Atomic model of the bacterial flagellar hook based on docking an X-ray derived structure and terminal two alpha-helices into an 7.1 angstrom resolution cryoEM map
7CGO 2020-07-01T00:00:00+0000 3.9 Cryo-EM structure of the flagellar motor-hook complex from Salmonella
2BGY 2005-01-06T00:00:00+0000 20.0 Fit of the x-ray structure of the baterial flagellar hook fragment flge31 into an EM map from the hook of Caulobacter crescentus.

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Flagellar hook protein FlgE P0A1J1 FLGE_SALTY
100.0 Flagellar hook protein FlgE P0A1J2 FLGE_SALTI