3MYD

Structure of the Cytoplasmic domain of FlhA from Helicobacter pylori

Summary for 3MYD

• Entry DOI: 10.2210/pdb3myd/pdb
• Descriptor: Flagellar biosynthesis protein flhA (2 entities in total)
• Functional Keywords: flha, flagellar export, type iii secretion, cytoplasmic fragment, protein transport
• Biological source: Helicobacter pylori (Campylobacter pylori)
• Cellular location: Cell membrane ; Multi-pass membrane protein : Q9ZM40
• Total number of polymer chains: 1
• Total formula weight: 40972.36

Authors

Moore, S.A.,Jia, Y. (deposition date: 2010-05-10, release date: 2010-05-26, Last modification date: 2024-02-21)

Primary citation

Moore, S.A.,Jia, Y.
Structure of the cytoplasmic domain of the flagellar secretion apparatus component FlhA from Helicobacter pylori.
J.Biol.Chem., 285:21060-21069, 2010

PubMed Abstract: Using x-ray crystallography we have determined the structure of the cytoplasmic fragment (residues 384-732) of the flagellum secretion system protein FlhA from Helicobacter pylori at 2.4-A resolution (r = 0.224; R(free) = 0.263). FlhA proteins and their type III secretion homologues contain an N-terminal integral membrane domain (residues 1-350), a linker segment, and a globular C-terminal cytoplasmic region. The tertiary structure of the cytoplasmic fragment contains a thioredoxin-like domain, an RNA recognition motif-like domain inserted within the thioredoxin-fold, a helical domain, and a C-terminal beta/alpha domain. Inter-domain contacts are extensive and the H. pylori FlhA structure appears to be in a closed conformation where the C-terminal domain closes against the RNA recognition motif-fold domain. Highly conserved surface residues in FlhA proteins are concentrated on a narrow surface strip comprising the thioredoxin-like and helical domains, possibly close to the export channel opening. The conformation of the FlhA N-terminal linker segment suggests a likely orientation for the FlhA cytoplasmic fragment relative to the membrane-embedded export pore. Comparison with the recently published structures of the Salmonella FlhA cytoplasmic fragment and its type III secretion counterpart InvA highlight a conformational change where the C-terminal beta/alpha domain in H. pylori FlhA moves 15 A relative to Salmonella FlhA. The conformational change is complex but primarily involves hinge-like movements of the helical and C-terminal domains. Interpretation of previous mutational screens suggest that the C-terminal domain of FlhA(C) plays a regulatory role in substrate class switching in flagellum export.

PubMed: 20442410
DOI: 10.1074/jbc.M110.119412

Experimental method

X-RAY DIFFRACTION (2.4 Å)