Multiple conformations of the metal-bound pyoverdine PvdI, a siderophore of Pseudomonas aeruginosa: a nuclear magnetic resonance study.
Under iron-deficient conditions, the Gram-negative bacterium Pseudomonas aeruginosa ATCC 15692 secretes a peptidic siderophore, pyoverdine PvdI, composed of an aromatic chromophore derived from 2,3-diamino-6,7-dihydroxyquinoline and a partially cyclized octapeptide, d-Ser- l-Arg- d-Ser- l-FoOHOrn-( l-Lys- l-FoOHOrn- l-Thr- l-Thr), in which the C-terminal carboxyl group forms a peptidic bond with the primary amine of the l-Lys side chain. In aqueous solution at room temperature, the (1)H NMR spectrum of pyoverdine PvdI-Ga(III) showed clear evidence of exchange broadening. At 253 K, two distinct conformations were observed and the measurement of structural constraints was possible. The three-dimensional structures of the two PvdI-Ga(III) conformers were determined, and analysis of the structures indicates that the observed conformational exchange involves a stereoisomerization of the metal binding coordination accompanied by a change in the global shape of the siderophore. This conformational transition was further characterized by heteronuclear relaxation experiments. The possible implications of this dynamic behavior for siderophore recognition by the receptor FpvAI are discussed.
Wasielewski
Emeric
E
Laboratoire de Biologie et de Génomique Structurales, Biomolecular NMR group, IGBMC UMR 7104 CNRS, ESBS, bd Sébastien Brandt BP 10413, 67404 Illkirch Cedex, France.
Tzou
Der-Lii
DL
Dillmann
Baudoin
B
Czaplicki
Jerzy
J
Abdallah
Mohamed A
MA
Atkinson
R Andrew
RA
Kieffer
Bruno
B
D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D005708:Gallium / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D019897:Periplasm / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D021381:Protein Transport; D017262:Siderophores / Q000737:chemistry* / Q000378:metabolism
D001426:Bacterial Proteins; D009842:Oligopeptides; D017262:Siderophores; C042453:pyoverdin; D005708:Gallium