Das Mousumi, Kumar Ritesh, Dubey Vikash K
Department of Biotechnology, Indian Institute of Technology Guwahati, Assam, -781039, India.
Protein Pept Lett. 2015;22(2):130-6. doi: 10.2174/0929866521666140616115357.
Leishmaniasis is a wide spread tropical disease caused by protozoan parasite Leishmania which belongs to order kinetoplastida and family trypanosomatidae. Ornithine decarboxylase is key enzyme in polyamine biosynthesis in Leishmania donovani. Here, we report biochemical characterization of ornithine decarboxylase from L. donovani. Furthermore, we have also investigated the role of N-terminal extension (250 amino acids) found in ornithine decarboxylase of L. donovani (LdODC). The removal of N-terminal extended region of LdODC results in improved stability of the protein. However, the truncated LdODC does not show any activity. Apparently, while N-terminal extended region of LdODC helps in proper folding of the protein for catalytic activity, there is a stability trade-off. The native full length LdODC with N-terminal extension has activity but lower stability. Thus, there is trade off of conformational stability for enzyme activity. Comparison of biochemical properties of both, fulllength and truncated enzymes, have provided interesting insights about the role of N-terminal extension in the protein.
利什曼病是一种广泛传播的热带疾病，由原生动物寄生虫利什曼原虫引起，该寄生虫属于动质体目锥虫科。鸟氨酸脱羧酶是杜氏利什曼原虫多胺生物合成中的关键酶。在此，我们报告了杜氏利什曼原虫鸟氨酸脱羧酶的生化特性。此外，我们还研究了在杜氏利什曼原虫鸟氨酸脱羧酶（LdODC）中发现的N端延伸（250个氨基酸）的作用。去除LdODC的N端延伸区域可提高蛋白质的稳定性。然而，截短的LdODC没有显示出任何活性。显然，虽然LdODC的N端延伸区域有助于蛋白质正确折叠以实现催化活性，但存在稳定性权衡。具有N端延伸的天然全长LdODC具有活性但稳定性较低。因此，存在构象稳定性与酶活性的权衡。全长酶和截短酶的生化特性比较为N端延伸在蛋白质中的作用提供了有趣的见解。
