Degradation pathway and generation of monohydroxamic acids from the trihydroxamate siderophore deferrioxamine B.
Siderophores are avid ferric ion-chelating molecules that sequester the metal for microbes. Microbes elicit siderophores in numerous and different environments, but the means by which these molecules reenter the carbon and nitrogen cycles is poorly understood. The metabolism of the trihydroxamic acid siderophore deferrioxamine B by a Mesorhizobium loti isolated from soil was investigated. Specifically, the pathway by which the compound is cleaved into its constituent monohydroxamates was examined. High-performance liquid chromatography and mass-spectroscopy analyses demonstrated that M. loti enzyme preparations degraded deferrioxamine B, yielding a mass-to-charge (m/z) 361 dihydroxamic acid intermediate and an m/z 219 monohydroxamate. The dihydroxamic acid was further degraded to yield a second molecule of the m/z 219 monohydroxamate as well as an m/z 161 monohydroxamate. These studies indicate that the dissimilation of deferrioxamine B by M. loti proceeds by a specific, achiral degradation and likely represents the reversal by which hydroxamate siderophores are thought to be synthesized.
Pierwola
Agnes
A
Department of Biology, Loyola University of Chicago, Chicago, Illinois 60626, USA.
Krupinski
Tomasz
T
Zalupski
Peter
P
Chiarelli
Michael
M
Castignetti
Domenic
D
D020561:Alphaproteobacteria / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D003676:Deferoxamine / Q000737:chemistry / Q000378:metabolism*; D006867:Hydrolases / Q000378:metabolism; D006877:Hydroxamic Acids / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D017262:Siderophores / Q000737:chemistry / Q000378:metabolism*; D012988:Soil Microbiology
D006877:Hydroxamic Acids; D017262:Siderophores; D006867:Hydrolases; D003676:Deferoxamine