Mycobacterium tuberculosis 16-kDa antigen (Hsp16.3) functions as an oligomeric structure in vitro to suppress thermal aggregation
Mycobacterium tuberculosis 16-kDa antigen (Hsp16.3) functions as an oligomeric structure in vitro to suppress thermal aggregation
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DOI：
10.1074/jbc.271.12.7218
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发表时间：
1996-03-22
影响因子：
4.8
通讯作者：
Quiocho, FA
中科院分区：
文献类型：
--
作者：
Chang, ZY;Primm, TP;Quiocho, FA
结核病仍然是威胁全世界数百万人生命的主要疾病。已经克隆了几种由单克隆抗体鉴定的结核分枝杆菌抗原，并正在开发改进的疫苗和诊断试剂。我们表达并纯化了18-kDa抗原，一种具有血清学诊断价值的免疫显性抗原，该抗原先前已被克隆并显示与α-晶状体蛋白相关的小热休克蛋白家族具有低序列同源性。沉降平衡分析超离心和动态光散射证明形成了一种特定的低聚物，149 +/- 8 kDa，由大约9个单体组成。在4 M尿素中，产生47 +/-6 kDa的较小寡聚体（或三聚体）。通过电子低温显微镜分析揭示了三角形的低聚物结构所产生的三个亚粒子或小球的存在。总之，数据表明三聚体的三聚体的抗原复合物结构。这种抗原，独立于ATP的添加，有效地抑制柠檬酸合酶在40摄氏度的热聚集，表明它可以在体外作为分子伴侣。抗原和热变性柠檬酸合酶之间的复合物可以使用高效液相色谱法检测和分离。我们建议重新命名为16 kDa的抗原Hsp16.3，以与小的热休克蛋白家族的其他成员一致。
Tuberculosis continues to be a major disease threatening millions of lives worldwide. Several antigens of Mycobacferium tuberculosis, identified by monoclonal antibodies, have been cloned and are being exploited in the development of improved vaccines and diagnostic reagents. We have expressed and purified the 18-kDa antigen, an immunodominant antigen with serodiagnostic value, which has been previously cloned and shown to share low sequence homology with the alpha-crystallin-related small heat shock protein family. Sedimentation equilibrium analytical ultracentrifugation and dynamic light scattering demonstrate the formation of a specific oligomer, 149 +/- 8 kDa, consisting of approximately nine monomers. In 4 M urea, a smaller oligomer of 47 +/- 6 kDa (or trimer) is produced. Analysis by electron cryomicroscopy reveals a triangular shaped oligomeric structure arising from the presence of three subparticles or globules. Taken together, the data suggest an antigen complex structure of a trimer of trimers. This antigen, independent of ATP addition, effectively suppresses the thermal aggregation of citrate synthase at 40 degrees C, indicating that it can function as a molecular chaperone in vitro. A complex between the antigen and heat-denatured citrate synthase can be detected and isolated using high performance Liquid chromatography. We propose to rename the 16-kDa antigen Hsp16.3 to be consistent with other members of the small heat shock protein family.