Multiple haem-utilization loci in Helicobacter pylori

A siderophore synthesis mutant of Escherichia coli was converted with an ordered cosmid library of Helicobacter pylori NCTC 11638 to determine the genes responsible for the use of heme as an iron source in H. pylori. Four independent cosmids were found that can complement this mutant on iron-restrictive solid media containing various heme compounds as the only source of iron. One of the cosmids was able to complement E. coli aroB hemA, suggesting that the heme molecule is taken up as a whole by this heme-biosynthesis mutant.