Mishra Pushpa, Choudhary Sinjan, Hosur Ramakrishna V
Department of Chemical sciences, Tata Institute of Fundamental Research, Mumbai, India.
UM-DAE Centre for Excellence in Basic Sciences, Mumbai University Campus, Mumbai, India.
Biophys Chem. 2015 May-Jun;200-201:27-33. doi: 10.1016/j.bpc.2015.03.008. Epub 2015 Mar 28.
Toxoplasma gondii is an apicomplexan parasite, which causes toxoplasmosis. Toxoplasma P2 (TgP2) is a ribosomal protein and exists as supramolecular assembly with other proteins in the ribosome. It is also shown that TgP2 is involved in some extra ribosomal functions. However, till date the protein has evaded structural characterization by any of the known techniques. In this background, we report here a systematic study using a variety of biophysical techniques and NMR, under different conditions of pH and temperature, and deduce that TgP2 consists of only helices and unstructured regions, is a monomer at low pH but forms multimers at higher pH, and has intrinsically a molten globule structure. The C-terminal half is flexible and the helices are concentrated in the N-terminal half of the chain. The dynamism inherent to the molten globule structure may have functional implications for its extra-ribosomal functions. which is contrast to that of human P2.
刚地弓形虫是一种顶复门寄生虫，可引起弓形虫病。弓形虫P2（TgP2）是一种核糖体蛋白，在核糖体中与其他蛋白质以超分子组装形式存在。研究还表明，TgP2参与一些核糖体以外的功能。然而，迄今为止，该蛋白尚未通过任何已知技术进行结构表征。在此背景下，我们在此报告一项系统研究，该研究在不同的pH和温度条件下使用了多种生物物理技术和核磁共振技术，推断出TgP2仅由螺旋和无结构区域组成，在低pH下为单体，但在较高pH下形成多聚体，并且本质上具有熔球结构。C端一半是灵活的，螺旋集中在链的N端一半。熔球结构固有的动态性可能对其核糖体以外的功能具有功能意义。这与人类P2的情况形成对比。
