Outer membrane-associated deoxyribonuclease activity of Porphyromonas gingivalis.
Extracellular outer membrane vesicles which are produced by Gram-negative bacteria may enclose deoxyribonucleic acid (DNA). While characterizing vesicles of Porphyromonas gingivalis, it was found that they do not contain detectable amount of DNA. It was also shown that the presence of deoxyribonuclease activity on whole cells and vesicles can degrade plasmidic and linear DNA. Deoxyribonuclease activity was also demonstrated in several other Gram-negative oral bacterial species. The nuclease activity of P. gingivalis was further characterized. When deoxyribonuclease activity was analyzed by zymography, only one active band was detected under the conditions tested. This nuclease enzyme showed a molecular weight of approximately 50 kDa. The activity was inhibited by 5 mM ZnCl2 or 100 mM EDTA whereas Mg2+ or Ca2+ ions were not required for activity. Activity was totally destroyed by treatment at 70 degrees C for 15 min. Although the enzyme may participate in virulence or provide nucleic acid precursors for bacterial growth, its exact role is still unknown.
Leduc
A
A
Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire and Département de Biochimie, Faculté des Sciences et de Génie, Université Laval, Ste-Foy, Québec, Canada.
Grenier
D
D
Mayrand
D
D