牙龈卟啉单胞菌细胞分裂蛋白质FtsZ的GTPase活性的热稳定性

Thermostability of GTPase activity of cell division protein FtsZ in Porphyromonas gingivalis

目的:探讨牙龈卟啉单胞菌(Pg)细胞分裂蛋白质FtsZ(PgFtsZ)的GTPase活性的热稳定性,阐明PgFtsZ的生物化学特性,为牙周病的治疗提供实验依据。方法:采用Malachite green assay法检测GTPase的活性,活性测定蛋白质为重组野生型PgFtsZ(WtPgFtsZ)和4种重组C末端缺失变异型PgFtsZ,即ZΔC01(C末端缺失73个氨基酸残基)、ZΔC02(C末端缺失128个氨基酸残基)、ZΔC03(C末端缺失177个氨基酸残基)和ZΔC04(C末端缺失233个氨基酸残基),各种PgFtsZ在未经处理时及煮沸加热处理5和10min后检测GTPase的酶活力值。结果:重组ZΔC04GTPase的活性在煮沸加热处理5和10min时均比未加热处理时的酶活性增加(P<0.05),重组WtPgFtsZ、ZΔC01、ZΔC02和ZΔC03在煮沸加热处理5min时GTPase的活性均较未煮沸加热处理时的活性增加(P<0.05),但进一步煮沸加热处理10min时,其GTPase的活性与未加热处理时相似。结论:Pg FtsZ是一种耐热蛋白质,并且C末端缺失233个氨基酸残基的缺失变异型ZΔC04表现出更强的耐热性能。

Objective To investigate the thermostability of GTPase activity of cell division protein FtsZ in Porphyromonas gingivalis（Pg） and to discuss the biochemical properties of FtsZ,and to provide experimental basis for curing periodontal disease.Methods Malachite green assay was used to measure the the GTPase activities of recombinant Wt PgFtsZ,ZΔC01（missing 73 residues from the C-terminus of PgFtsZ）,ZΔC02（missing 128 residues from the C-terminus of PgFtsZ）,ZΔC03（missing 177 residues from the C-terminus of PgFtsZ）,and ZΔC04（missing 233 residues from the C-terminus of PgFtsZ）.The GTPase activities of different kinds of proteins were detected after the protein dealed with unboiling and boiling for 5 and 10 min.The values of GTPase activities were detected at A650nm.Results The GTPase activities of ZΔC04 boiled for 5 and 10 min were higher than those of unboiled（P〈0.05）.The GTPase activities of WtPgFtsZ,ZΔC01,ZΔC02,and ZΔC03 boiled for 5 min were higher than those of unboiled（P〈0.05）.But the GTPase activities of WtPgFtsZ,ZΔC01,ZΔC02,and ZΔC03 boiled for 10 min were similar to those of unboiled.Conclusion Pg FtsZ is a kind of protein with thermostability,and ZΔC04 missing 233 residues from the C-terminus has higher thermostability.