Siderophore peptide, a new type of post-translationally modified antibacterial peptide with potent activity.
Microcin E492 (MccE492, 7886 Da), the 84-amino acid antimicrobial peptide from Klebsiella pneumoniae, was purified in a post-translationally modified form, MccE492m (8717 Da), from culture supernatants of either the recombinant Escherichia coli VCS257 strain harboring the pJAM229 plasmid or the K. pneumoniae RYC492 strain. Chymotrypsin digestion of MccE492m led to the MccE492m-(74-84) C-terminal fragment that carries the modification and that was analyzed by mass spectrometry and nuclear magnetic resonance at natural abundance. The 831-Da post-translational modification consists of a trimer of N-(2,3-dihydroxybenzoyl)-l-serine linked via a C-glycosidic linkage to a beta-d-glucose moiety, itself linked to the MccE492m Ser-84-carboxyl through an O-glycosidic bond. This modification, which mimics a catechol-type siderophore, was shown to bind ferric ions by analysis of the collision-induced dissociation pattern obtained for MccE492m-(74-84) by electrospray ion trap mass spectrometry experiments in the presence of FeCl(3). By using a series of wild-type and mutant isogenic strains, the three catechol-type siderophore receptors Fiu, Cir, and FepA were shown to be responsible for the recognition of MccE492m at the outer membrane of sensitive bacteria. Because MccE492m shows a broader spectrum of antibacterial activity and is more potent than MccE492, we propose that by increasing the microcin/receptor affinity, the modification leads to a better recognition and subsequently to a higher antimicrobial activity of the microcin. Therefore, MccE492m is the first member of a new class of antimicrobial peptides carrying a siderophore-like post-translational modification and showing potent activity, which we term siderophore-peptides.
Thomas
Xavier
X
Laboratoire de Chimie et Biochimie des Substances Naturelles, UMR 5154 CNRS USM 502, the Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, 63 Rue Buffon, 75005 Paris.
Destoumieux-Garzón
Delphine
D
Peduzzi
Jean
J
Afonso
Carlos
C
Blond
Alain
A
Birlirakis
Nicolas
N
Goulard
Christophe
C
Dubost
Lionel
L
Thai
Robert
R
Tabet
Jean-Claude
JC
Rebuffat
Sylvie
S
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001430:Bacteriocins / Q000737:chemistry / Q000494:pharmacology*; D002396:Catechols / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D002712:Chlorides; D002918:Chymotrypsin / Q000737:chemistry; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry; D007711:Klebsiella pneumoniae / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D002396:Catechols; D002712:Chlorides; D005290:Ferric Compounds; D010455:Peptides; C020411:microcin; D002918:Chymotrypsin; C024555:ferric chloride