Purification and characterization of rhodobactin: a mixed ligand siderophore from Rhodococcus rhodochrous strain OFS.
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.
Dhungana
Suraj
S
Bioscience, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA.
Michalczyk
Ryszard
R
Boukhalfa
Hakim
H
Lack
Joseph G
JG
Koppisch
Andrew T
AT
Fairlee
Jason M
JM
Johnson
Mitchell T
MT
Ruggiero
Christy E
CE
John
Seth G
SG
Cox
Matthew M
MM
Browder
Cindy C
CC
Forsythe
Jennifer H
JH
Vanderberg
Laura A
LA
Neu
Mary P
MP
Hersman
Larry E
LE
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
D008024:Ligands; D008670:Metals; D010455:Peptides; D017262:Siderophores; C037919:N,N-dimethylepinephrine; D000362:Agar; D007501:Iron; D004837:Epinephrine