Transport of Intact Porphyrin by HpuAB, the Hemoglobin-Haptoglobin Utilization System of Neisseria meningitidis

The meningococcal hemA gene was cloned and used to construct a porphyrin biosynthesis mutant. An analysis of the hemA mutant indicated that meningococci can transport intact porphyrin from heme (Hm), hemoglobin (Hb), and Hb-haptoglobin (Hp). By constructing a HemA(−) HpuAB(−) double mutant, we demonstrated that HpuAB is required for the transport of porphyrin from Hb and Hb-Hp.