Guo, Maolin

Harvey, Ian

Yang, Weiping

Coghill, Lorraine

Campopiano, Dominic J

Parkinson, John A

MacGillivray, Ross T A

Harris, Wesley R

Sadler, Peter J

13

2005-01-31T16:56:29Z

2005-01-31T16:56:29Z

2003-10-07

The 34-kDa periplasmic iron-transport protein (FBP) from Neisseria gonorrhoeae (nFBP) contains Fe(III) and (hydrogen)phosphate (synergistic anion). It has a characteristic ligand-to-metal charge-transfer absorption band at 481 nm. Phosphate can be displaced by (bi)carbonate to give Fe.CO3.nFBP (lamda max 459 nm). The local structures of native Fe-PO4-nFBP and Fe.CO3.nFBP were determined by EXAFS at the FeK edge using full multiple scattering analysis. The EXAFS analysis reveals that both phosphate and carbonate ligands bind to FBP in monodentate mode in contrast to transferrins, which bind carbonate in bidentate mode. The EXAFS analysis also suggests an alternative to the crystallographically determined position of the Glu ligand, and this in turn suggests that an H-bonding network may help to stabilize monodentate binding of the synergistic anion. The anions oxalate, pyrophosphate, and nitrilotriacetate also appear to serve as synergistic anions but not sulfate or perchlorate. The oxidation of Fe(II) in the presence of nFBP led to a weak Fe(III).nFBP complex (lamda max 471 nm). Iron and phosphate can be removed from FBP at low pH (pH 4.5) in the presence of a large excess of citrate. Apo-FBP is less soluble and less stable than Fe.nFBP and binds relatively weakly to Ga(III) and Bi(III) but not to Co(III) ions, all of which bind strongly to apo-human serum transferrin.

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Journal of Biological Chemistry (2003), 278(4), 2490-2502

http://www.jbc.org

DOI 10.1074/jbc.M208776200

http://hdl.handle.net/1842/662

en

© 2003 The American Society for Biochemistry and Molecular Biology, Inc.

Synergistic action

Metal Binding

Ferric Ion-Binding Protein

Neisseria Gonorrhoeae

Synergistic Anion and Metal Binding to the Ferric Ion-binding Protein from Neisseria gonorrhoeae

Article