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Iron traffics in circulation bound to a siderocalin (Ngal)-catechol complex
Guanhu Bao1, Matthew Clifton, Trisha M Hoette
1College of Physicians and Surgeons of Columbia University, New York, New York, USA.
Nature Chemical Biology
|June 29, 2010
Summary
Neutrophil gelatinase-associated lipocalin (Scn-Ngal) binds iron and catechol, forming a complex that transports iron in aseptic conditions. This discovery reveals a new microbial-host interaction and potential link to various diseases.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Lipocalins are secreted proteins binding small organic molecules.
- Scn-Ngal sequesters bacterial siderophores, inhibiting bacterial growth.
- Scn-Ngal's role in aseptic diseases suggests additional ligands and functions.
Purpose of the Study:
- To identify additional ligands bound by Scn-Ngal.
- To elucidate the function of Scn-Ngal in aseptic conditions.
- To understand the mechanism of iron transport by Scn-Ngal.
Main Methods:
- Chemical screens
- Crystallography
- Fluorescence assays
- In vivo studies
Main Results:
- Scn-Ngal binds iron and catechol, forming a stable complex.
- The Scn-Ngal-catechol-Fe(III) complex prevents iron reactivity and facilitates in vivo transport.
- Scn-Ngal recycles iron in endosomes via a pH-sensitive mechanism.
- Catechols are derived from microbial and mammalian metabolism.
Conclusions:
- Scn-Ngal binds an endogenous siderophore (catechol) for iron transport in aseptic tissues.
- This represents a novel microbial-host interaction.
- The findings may link Scn-Ngal's diverse roles in different diseases.
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