3myd | pdb_00003myd
Structure of the Cytoplasmic domain of FlhA from Helicobacter pylori
Structural highlights
Function[FLHA_HELPJ] Involved in the export of flagellum proteins. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedUsing 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. Structure of the cytoplasmic domain of the flagellar secretion apparatus component FlhA from Helicobacter pylori.,Moore SA, Jia Y J Biol Chem. 2010 Jul 2;285(27):21060-9. Epub 2010 May 4. PMID:20442410[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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