title: Dimeric WH2 repeats of VopF sequester actin monomers into non-nucleating linear string conformations: An X-ray scattering study.
abstract: VopF and VopL are highly similar virulence-factors of Vibrio cholerae and Vibrio parahaemolyticus respectively that disrupt the host's actin cytoskeleton, using a unique organization in dimerized WH2 repeats. Association of dimerized WH2 domains with the barbed face of actin confers multifunctional activities to VopF in vitro, including G-actin sequestration and filament nucleation, barbed end tracking and uncapping. Here, small angle X-ray scattering (SAXS) measurements of complexes of VopF with actin and structural modeling reveal that VopF stabilizes linear actin-strings that differ from canonical actin filament architectures but represent non-polymerizable sequestered forms of actin. The results exclude that VopL binds the pointed end of actin filaments in the template filament nucleation mechanism derived from crystallographic studies.
authors.affiliation: Cytoskeleton Dynamics and Motility Group, CNRS, Gif-sur-Yvette, France. Electronic address: balendu.avvaru@gmail.com.
authors.forename: Balendu Sankara
authors.initials: BS
authors.lastname: Avvaru
authors.affiliation: Cytoskeleton Dynamics and Motility Group, CNRS, Gif-sur-Yvette, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Pernier
authors.affiliation: Cytoskeleton Dynamics and Motility Group, CNRS, Gif-sur-Yvette, France. Electronic address: carlier@lebs.cnrs-gif.fr.
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Carlier
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D019281:Dimerization; D008958:Models, Molecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D053838:Scattering, Small Angle; D014734:Vibrio cholerae / Q000737:chemistry*; D037521:Virulence Factors / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D037521:Virulence Factors
keywords: Actin; SAXS; VopF; WH2 domain repeats