The Role of Heme Binding by DNA-protective Protein from Starved Cells (Dps) in the Tolerance of Porphyromonas gingivalis to Heme Toxicity |
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| Authors: | Jin-Long Gao Yanling Lu Gina Browne Benjamin C-M Yap Jill Trewhella Neil Hunter Ky-Anh Nguyen |
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| Institution: | From the ‡Faculty of Dentistry and ;¶School of Molecular Bioscience, The University of Sydney, New South Wales 2006 and ;the §Institute of Dental Research, Westmead Millennium Institute and Westmead Centre for Oral Health, Westmead Hospital, Westmead, New South Wales 2145, Australia |
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| Abstract: | The widely expressed DNA-protective protein from starved-cells (Dps) family proteins are considered major contributors to prokaryotic resistance to stress. We show here that Porphyromonas gingivalis Dps (PgDps), previously described as an iron-storage and DNA-binding protein, also mediates heme sequestration. We determined that heme binds strongly to PgDps with an apparent Kd of 3.7 × 10−8
m and is coordinated by a single surface-located cysteine at the fifth axial ligand position. Heme and iron sequestered in separate sites by PgDps provide protection of DNA from H2O2-mediated free radical damage and were found to be important for growth of P. gingivalis under excess heme as the only iron source. Conservation of the heme-coordinating cysteine among Dps isoforms from the Bacteroidales order suggests that this function may be a common feature within these anaerobic bacteria. |
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| Keywords: | DNA Damage Ferritin Heme Ligand-binding Protein Oxidative Stress Protein Structure X-ray Scattering DNA Protection Dps |
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