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Titolo:
THE PERIODONTOPATHOGEN PORPHYROMONAS-GINGIVALIS BINDS IRON PROTOPORPHYRIN-IX IN THE MU-OXO DIMERIC FORM - AN OXIDATIVE BUFFER AND POSSIBLE PATHOGENIC MECHANISM
Autore:
SMALLEY JW; SILVER J; MARSH PJ; BIRSS AJ;
Indirizzi:
UNIV LIVERPOOL,DEPT CLIN DENT SCI,ORAL BIOL UNIT LIVERPOOL L69 3BX MERSEYSIDE ENGLAND UNIV GREENWICH,SCH CHEM & LIFE SCI LONDON SE18 6PF ENGLAND
Titolo Testata:
Biochemical journal
, volume: 331, anno: 1998,
parte:, 3
pagine: 681 - 685
SICI:
0264-6021(1998)331:<681:TPPBIP>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXTRACELLULAR MEMBRANE-VESICLES; HEMIN-BINDING; W50; VIRULENCE; COMPLEXES; MOSSBAUER; PHYSIOLOGY; HEMOPEXIN; PROTEINS; LIGANDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
J.W. Smalley et al., "THE PERIODONTOPATHOGEN PORPHYROMONAS-GINGIVALIS BINDS IRON PROTOPORPHYRIN-IX IN THE MU-OXO DIMERIC FORM - AN OXIDATIVE BUFFER AND POSSIBLE PATHOGENIC MECHANISM", Biochemical journal, 331, 1998, pp. 681-685

Abstract

Mossbauer spectroscopy was used to re-evaluate iron protoporphyrin IX, FePPIX, binding and the chemical nature of the black iron porphyrin pigment of Porphyromonas gingivalis. We demonstrate that FePPIX is bound to the cell in the mu-oxo dimeric form, [Fe(III)PPIX](2)O, and thatthe iron porphyrin pigment is also composed of this material. P. gingivalis also assimilated monomeric Fe(II)- and Fe(III)PPIX into mu-oxo dimers in vitro. Scatchard analysis revealed a greater binding maximumof cells for mu-oxo dimers than for monomeric Fe(III)- or Fe(II)PPIX,although the relative affinity constant for the dimers was lower. Formation of [Fe(III)PPIX](2)O via reactions of Fe(II)PPIX with oxygen, and its toxic derivatives, would serve as an oxidative buffer and permit P. gingivalis and other black-pigmenting anaerobes to engender and maintain a local anaerobic environment. Tying up of free oxygen specieswith iron protoporphyrin IX would also reduce and limit Fe(II)PPIX-mediated oxygen-radical cell damage. More importantly, formation of a cell-surface mu-oxo dimer layer may function as a protective barrier against assault by reactive oxidants generated by neutrophils. Selective interference with these mechanisms would offer the possibility of attenuating the pathogenicity of P. gingivalis and other iron protoporphyrin IX-binding pathogens whose virulence is regulated by this reactive molecule.

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Documento generato il 04/12/20 alle ore 15:48:00