TABLE 6.

Proteins involved in uptake of iron and heme by Haemophilus influenzae^a

Protein	Gene	Molecular mass (kDa)	Location	Function	References
Tbp1	tbpA	95	Outer membrane	Transferrin transport	111, 112, 179
Tbp2	tbpB	68–85	Outer membrane	Transferrin binding	111, 112, 179
FbpA	hitA	36	Periplasmic space	Iron binding	272
HitB	hitB	51	Cytoplasmic membrane	Permease	272
HitC	hitC	40	Cytoplasmic membrane	Energy transduction	272
HxuA	hxuA	100	Secreted	Heme/hemopexin binding	65, 66
HxuB	hxuB	60	Outer membrane	Release of HxuA	66
HxuC	hxuC	78	Outer membrane	Heme transport	66
57-kDa protein	?	57	Outer membrane	Hemopexin binding	350, 351
HbpA	hbpA	61	?	Heme binding	131
HgpA	hgpA	120	Outer membrane	Hemoglobin/haptoglobin binding	150
HgpB	hgpB	115	?	Hemoglobin/haptoglobin binding	257
HhuA	hhuA	115	Outer membrane	Hemoglobin/haptoglobin binding	185
P4	hel	30	Outer membrane	Heme transport	256

^aAdapted from reference 249 with permission of the publisher.