title: Conformational analysis by CD and NMR spectroscopy of a peptide encompassing the amphipathic domain of YopD from Yersinia.
abstract: To establish an infection, Yersinia pseudotuberculosis utilizes a plasmid-encoded type III secretion machine that permits the translocation of several anti-host factors into the cytosol of target eukaryotic cells. Secreted YopD is essential for this process. Pre-secretory stabilization of YopD is mediated by an interaction with its cognate chaperone, LcrH. YopD possesses LcrH binding domains located in the N-terminus and in a predicted amphipathic domain located near the C-terminus. This latter domain is also critical for Yersinia virulence. In this study, we designed synthetic peptides encompassing the C-terminal amphipathic domain of YopD. A solution structure of YopD278-300, a peptide that strongly interacted with LcrH, was obtained by NMR methods. The structure is composed of a well-defined amphipathic alpha helix ranging from Phe280 to Tyr291, followed by a type I beta turn between residues Val292 and His295. The C-terminal truncated peptides, YopD278-292 and YopD271-292, lacked helical structure, implicating the beta turn in helix stability. An interaction between YopD278-300 and its cognate chaperone, LcrH, was observed by NMR through line-broadening effects and chemical shift differences between the free peptide and the peptide-LcrH complex. These effects were not observed for the unstructured peptide, YopD278-292, which confirms that the alpha helical structure of the YopD amphipathic domain is a critical binding region of LcrH.
authors.affiliation: Department of Organic Chemistry, Umeå University, Umeå, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Tengel
authors.forename: Ingmar
authors.initials: I
authors.lastname: Sethson
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Francis
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D015007:Yersinia / Q000737:chemistry
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D018832:Molecular Chaperones; D010446:Peptide Fragments; C118339:SycD protein, bacteria; C078910:YopD protein, Yersinia