title: Purification and characterization of rhodobactin: a mixed ligand siderophore from Rhodococcus rhodochrous strain OFS.
abstract: The siderophore produced by Rhodococcus rhodochrous strain OFS, rhodobactin, was isolated from iron-deficient cultures and purified by a combination of XAD-7 absorptive/partition resin column and semi-preparative HPLC. The siderophore structure was characterized using 1D and 2D (1)H, (13)C and (15)N NMR techniques (DQFCOSY, TOCSY, NOESY, HSQC and LR-HSQC) and was confirmed using ESI-MS and MS/MS experiments. The structural characterization revealed that the siderophore, rhodobactin, is a mixed ligand hexadentate siderophore with two catecholate and one hydroxamate moieties for iron chelation. We further investigated the effects of Fe concentrations on siderophore production and found that Fe limiting conditions (Fe concentrations from 0.1 microM to 2.0 microM) facilitated siderophore excretion. Our interests lie in the role that siderophores may have in binding metals at mixed contamination sites (containing metals/radionuclides and organics). Given the broad metabolic capacity of this microbe and its Fe scavenging ability, R. rhodochrous OFS may have a competitive advantage over other organisms employed in bioremediation.
authors.affiliation: Bioscience, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA.
authors.forename: Suraj
authors.initials: S
authors.lastname: Dhungana
authors.forename: Ryszard
authors.initials: R
authors.lastname: Michalczyk
authors.forename: Hakim
authors.initials: H
authors.lastname: Boukhalfa
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Lack
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Koppisch
authors.forename: Jason M
authors.initials: JM
authors.lastname: Fairlee
authors.forename: Mitchell T
authors.initials: MT
authors.lastname: Johnson
authors.forename: Christy E
authors.initials: CE
authors.lastname: Ruggiero
authors.forename: Seth G
authors.initials: SG
authors.lastname: John
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Cox
authors.forename: Cindy C
authors.initials: CC
authors.lastname: Browder
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Forsythe
authors.forename: Laura A
authors.initials: LA
authors.lastname: Vanderberg
authors.forename: Mary P
authors.initials: MP
authors.lastname: Neu
authors.forename: Larry E
authors.initials: LE
authors.lastname: Hersman
mesh_terms: D000362:Agar / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004837:Epinephrine / Q000031:analogs & derivatives / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry; D012240:Rhodococcus / Q000378:metabolism*; D017262:Siderophores / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013053:Spectrophotometry / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013997:Time Factors
chemical_list: D008024:Ligands; D008670:Metals; D010455:Peptides; D017262:Siderophores; C037919:N,N-dimethylepinephrine; D000362:Agar; D007501:Iron; D004837:Epinephrine