Enzymatic iron oxidation by Leptothrix discophora: identification of an iron-oxidizing protein.
An iron-oxidizing factor was identified in the spent culture medium of the iron- and manganese-oxidizing bacterial strain Leptothrix discophora SS-1. It appeared to be a protein, with an apparent molecular weight of approximately 150,000. Its activity could be demonstrated after fractionation of the spent medium by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A spontaneous mutant of L. discophora SS-1 was isolated which excreted neither manganese- nor iron-oxidizing activity, whereas excretion of other proteins seemed to be unaffected. Although the excretion of both metal-oxidizing factors was probably linked, the difference in other properties suggests that manganese and iron oxidation represent two different pathways. With a dot-blot assay, it was established that different bacterial species have different metal-oxidizing capacities. Whereas L. discophora oxidized both iron and manganese, Sphaerotilus natans oxidized only iron and two Pseudomonas spp. oxidized only manganese.
Corstjens
P L
PL
Department of Biochemistry, Leiden University, The Netherlands.
de Vrind
J P
JP
Westbroek
P
P
de Vrind-de Jong
E W
EW
D001419:Bacteria / Q000378:metabolism; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006088:Gram-Negative Aerobic Bacteria / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism; D009154:Mutation; D010084:Oxidation-Reduction
D001426:Bacterial Proteins; D008345:Manganese; D007501:Iron