Hemin Regulation of Hemoglobin Binding by Porphyromonas gingivalis
| Autor: | John W. Smalley, Ailsa S. McKee, Andrew J. Birss, Philip Marsh |
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| Rok vydání: | 1998 |
| Předmět: |
Hemoglobin binding
Hemeprotein Applied Microbiology and Biotechnology Microbiology Hemoglobins chemistry.chemical_compound polycyclic compounds Animals heterocyclic compounds Porphyromonas gingivalis Bacteroidaceae Dose-Response Relationship Drug biology Binding protein Membrane Proteins Cooperative binding General Medicine equipment and supplies biology.organism_classification Kinetics Biochemistry chemistry Hemin Cattle Hemoglobin Oxidation-Reduction Protein Binding |
| Zdroj: | Current Microbiology. 36:102-106 |
| ISSN: | 1432-0991 0343-8651 |
| Popis: | Hemoglobin binding to chemostat-grown hemin-excess and hemin-limited cells of Porphyromonas gingivalis W50, and to cells of the avirulent, beige-pigmenting variant W50/BE1, was quantified. Hemin-excess W50 bound more hemoglobin than hemin-limited W50, mirroring the hemin-binding ability of these cells [Microb Ecol Health Dis 7:9-15, 1994]. In contrast to hemin, hemoglobin binding was not enhanced by sodium dithionite. The hemoglobin-binding capacity of hemin-excess W50/BE1 was below that of hemin-limited W50 and only observed under oxidizing conditions. Scatchard analysis revealed similar affinity constants for hemin-excess and hemin-limited W50, and confirmed a lower binding maximum for the latter. Hemin-excess W50/BE1 displayed cooperative binding of hemoglobin. These differences in binding were reflected in the binding of a horse radish peroxidase-conjugated hemoglobin (HHRPO) in a dot-blot assay. However, neither the 32-kDa hemin-binding protein, nor its 19-kDa heat-modified form, from either hemin-limited W50 or hemin-excess W50/BE1, bound this conjugate. These data indicate that hemoglobin binding by P. gingivalis is hemin-regulated and occurs via a mechanism different from hemin binding. |
| Databáze: | OpenAIRE |
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