Characterization of the ferrioxamine uptake system of Nitrosomonas europaea.
The chemolithoautotroph Nitrosomonas europaea has two genes predicted to encode outer-membrane (OM) ferrioxamine transporters. Expression of the ferrioxamine uptake system required induction, as shown by the shorter lag phase in ferrioxamine-containing cultures when ferrioxamine-exposed cells were used as an inoculum. The two OM ferrioxamine siderophore transporters encoded by foxA(1) (NE1097) and foxA(2) (NE1088) were produced only in cells grown in Fe-limited ferrioxamine-containing medium. The inactivation of foxA(1), singly or in combination with foxA(2), prevented growth in Fe-limited medium containing excess desferrioxamine (DFX). The foxA(2)-disrupted single mutant grew poorly in the regular Fe-limited (0.2 microM) medium with 10 microM DFX, but grew well when the Fe level was raised to 1.0 microM with 10 microM DFX. For efficient acquisition of Fe-loaded ferrioxamine, N. europaea needs both ferrioxamine transporters FoxA(1) and FoxA(2). FoxA(1) probably regulates its own production, and it controls the production of FoxA(2) as well.
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
Xueming
X
Wei
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
Luis A
LA
Sayavedra-Soto
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
Daniel J
DJ
Arp
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003676:Deferoxamine / Q000378:metabolism*; D005290:Ferric Compounds / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000378:metabolism; D008969:Molecular Sequence Data; D043370:Nitrosomonas europaea / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D005290:Ferric Compounds; C489524:FoxA protein, bacteria; D007502:Iron Chelating Agents; D011956:Receptors, Cell Surface; C002577:ferrioxamine B; D007501:Iron; D003676:Deferoxamine