血管性血友病因子裂解酶间隔区结构域突变对酶生物学功能的影响  

Effect of ADAMTS13 spacer domain mutations on biological function of enzyme

作　　者：王萌 吴昊 李华[3] 赵艺鸿 金圣宇[1,4] WANG Meng;WU Hao;LI Hua;ZHAO Yihong;JIN Shengyu(Department of Hematology,Affiliated Hospital,Yanbian University,Yanji 133000,China;Department of Rehabilitation,People’s Hospital,Shaoxing City,Zhejiang Province,Shaoxing 312000,China;Department of Physical Examination,Affiliated Hospital,Yanbian University,Yanji 133000,China;Central Laboratory,Affiliated Hospital,Yanbian University,Yanji 133000,China)

机构地区：[1]延边大学附属医院血液内科,吉林延吉133000 [2]浙江省绍兴市人民医院康复医学科,浙江绍兴312000 [3]延边大学附属医院体检科,吉林延吉133000 [4]延边大学附属医院中心实验室,吉林延吉133000

出　　处：《吉林大学学报（医学版）》2024年第4期900-907,共8页Journal of Jilin University：Medicine Edition

基　　金：国家自然科学基金项目(81660026,82060032);吉林省教育厅“十三五”科研项目[吉教科合字(2016)273号]。

摘　　要：目的:探讨血管性血友病因子裂解酶ADAM金属肽酶含血小板反应蛋白1型13(ADAMTS13)间隔区结构域在血管性血友病因子(vWF)裂解过程中的生物学功能,阐明ADAMTS13在血栓性血小板减少性紫癜(TTP)发病机制中的作用。方法:将ADAMTS13间隔区结构域中的氨基酸残基TEDRLPR以点突变技术逐个基因突变(突变体M1~M7),将构建的ADAMTS13与其突变体质粒转染至人胚肾HEK293细胞,稳定表达后提纯重组蛋白。观察野生型和突变型ADAMTS13在变性条件、剪切应力作用和ADAMTS13抗体处理后裂解vWF的能力。结果:荧光共振能量转移(FRET)实验,与野生型ADAMTS13比较,ADAMTS13突变体M4(R635A)和突变体M7(R638A)对FRET-vWF73剪切能力降低(P<0.05)。变性条件下,野生型ADAMTS13可以将vWF多聚体裂解,与野生型ADAMTS13比较,ADAMTS13突变体M4(R635A)和突变体M7(R638A)的裂解活性明显降低(P<0.01)。在体外剪切应力作用下,与野生型ADAMTS13比较,ADAMTS13突变体M4(R635A)和突变体M7(R638A)裂解vWF多聚体的能力明显降低(P<0.01)。与野生型ADAMTS13比较,ADAMTS13突变体M4(R635A)和突变体M7(R638A)与vWF之间的结合力差异无统计学意义(P>0.05),表明ADAMTS13的C末端与vWF之间存在多个结合位点。ADAMTS13抗体处理可在一定程度上抑制野生型和突变型ADAMTS13裂解vWF的能力。结论:间隔区突变后ADAMTS13的活性降低。ADAMTS13突变体M4(R635A)和突变体M7(R638A)可能是ADAMTS13在底物识别时的重要作用位点。Objective:To discuss the biological function of the spacer domain of ADAM metalloproteinase with thrombospondin type 1 motifs 13(ADAMTS13)in the cleaving process of von Willebrand factor(vWF),and to clarify the role of ADAMTS13 in the pathogenesis of thrombotic thrombocytopenic purpura(TTP).Methods:The point mutation method was introduced sequentially into the amino acid residues TEDRLPR of the ADAMTS13 spacer domain(mutants M1-M7)by site-directed mutagenesis.The constructed ADAMTS13 and its mutants plasmids were transfected into the human embryonic kidney HEK293 cells,and the recombinant proteins were purified after stable expression.The cleavage capabilities of both wild type and mutant ADAMTS13 were observed under denaturation conditions,shear stress,and after treatment with ADAMTS13 antibodies.Results:The fluorescence resonance energy transfer(FRET)assay results showed that compared with wild type ADAMTS13,the cleavage abilities of ADAMTS13 mutant M4(R635A)and mutant M7(R638A)on the FRET-vWF73 were decreased(P<0.05).Under denaturation conditions,the wild-type ADAMTS13 could cleave the vWF multimers;compared with wild-type ADAMTS13,the cleavage activities of ADAMTS13 mutant M4(R635A)and mutant M7(R638A)were significantly decreased(P<0.01).Under in vitro shear stress,compared with wild type ADAMTS13,the abilities of ADAMTS13 mutant M4(R635A)and mutant M7(R638A)to cleave vWF multimers were significantly decreased(P<0.01).Compared with wild type ADAMTS13,the binding affinity between vWF and ADAMTS13 mutant M4(R635A)and mutant M7(R638A)had no significant difference(P>0.05),indicating there were multiple binding sites between C-terminal of ADAMTS13 and vWF.The ADAMTS13 antibodies were able to inhibit the cleavage ability of both wildtype and mutant ADAMTS13 to some extent.Conclusion:The activity of ADAMTS13 after spacer domain mutation is decreased.The ADAMTS13 mutant M4(R635A)and mutant M7(R638A)may be the important action sites for ADAMTS13 in substrate recognition.

关 键 词：血管性血友病因子裂解酶 ADAM金属肽酶含血小板反应蛋白1型13 间隔区结构域 血管性血友病因子 血栓性血小板减少性紫癜 

分 类 号：R554.6[医药卫生—血液循环系统疾病]