Leptospira interrogans requires a functional heme oxygenase to scavenge iron from hemoglobin.
The transposon TnSC189 was used to construct a mutant in the putative heme oxygenase gene hemO (LB186) of Leptospira interrogans. Unlike its parent strain, the mutant grew poorly in medium in which hemoglobin was the sole iron source. The putative heme oxygenase was over expressed in a His-tagged form, purified and was demonstrated to degrade heme in vitro. Unexpectedly, it was also found that the L. interrogans growth rate was significantly increased when medium was supplemented with hemoglobin, but only if ferrous iron sources were absent. This result was mirrored in the expression of some iron-related genes and suggests the presence of regulatory mechanisms detecting Fe2+ and hemoglobin. This is the first demonstration of a functional heme oxygenase from a spirochete.
Australian Bacterial Pathogenesis Program, Department of Microbiology, Monash University, VIC, Australia.
Gerald L
GL
Murray
Katherine M
KM
Ellis
Miranda
M
Lo
Ben
B
Adler
D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D004251:DNA Transposable Elements; D017353:Gene Deletion; D015870:Gene Expression; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007921:Leptospira interrogans / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D003470:Culture Media; D004251:DNA Transposable Elements; D006454:Hemoglobins; D011994:Recombinant Proteins; D007501:Iron; D006419:Heme Oxygenase (Decyclizing)