关键词: 野生型和变异型牙龈卟啉单胞菌FtsZs, GTPase的活性

Abstract: Objective To investigate the effects of Ca²+and Mg²+on the GTPase activities of the wild-type and mutant FtsZs in Porphyromonas gingivalis. Methods Plasmids pEZ1 (Wt PgFtsZ), pYW1(missing 73 residues from the C-terminus of PgFtsZ, ZΔC01) and pYW2 (missing 43 residues from the N-terminus of PgFtsZ, ZΔN01) were introduced into Escherichia coli BL21(DE3)pLysS to express and purify the purpose proteins. Malachite green assay was used to measure the GTPase activities of purified Wt PgFtsZ, ZΔC01 and ZΔN01. Results GTPase activities of Wt PgFtsZ, ZΔC01 and ZΔN01 were 8.25±0.22, 7.43±0.23, 8.00±0.18, respectively, without no ion. GTPase activities of Wt PgFtsZ, ZΔC01 and ZΔN01 were 8.30±0.15, 7.51±0.22, 7.85±0.17, respectively, with 10 mmol•Ｌ^-1 Mg²⁺, and not affected by 10 mmol•L^-1 Mg²+（P>0.05）. However, GTPase activities of Wt PgFtsZ, ZΔC01 and ZΔN01 were 5.84±0.20, 5.25±0.18, 5.73±0.13, respectively, with 10 mmol•L^-1 Ca²+, and reduced by 10 mmol•L^-1 Ca²+（P<0.01）. Conclusion 10 mmol•L^-1 Mg²+ has no effect on GTPase activities of Wt PgFtsZ, ZΔC01 and ZΔN01. However, 10 mmol•L^-1 Ca²+ inhibits their GTPase activities.

Key words: wild-type PgFtsZs