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.
Wei
Xueming
X
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
Sayavedra-Soto
Luis A
LA
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
Arp
Daniel J
DJ
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
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