Soares-Costa A, Beltramini L M, Thiemann O H, Henrique-Silva F
Laboratory of Molecular Biology, DGE-Federal University of São Carlos, São Carlos-SP, Brazil.
Biochem Biophys Res Commun. 2002 Sep 6;296(5):1194-9. doi: 10.1016/s0006-291x(02)02046-6.
Plants possess several defense mechanisms against pathogenic attack. One of these defenses is the use of protease inhibitor proteins, which interfere in the development and growth of pathogens. Sugarcane productivity can be impacted by the plant's susceptibility to fungal diseases that result in production losses. A relevant line of investigation, therefore, is into the plant's natural defense mechanisms for the control of phytopathogens using cystatins-proteins that specifically inhibit cysteine proteases. In this paper, we discuss the expression, in Escherichia coli, of a sugarcane cystatin, its purification, antifungal activity, and circular dichroism to monitor correct folding. These studies revealed a secondary structure similar to that of the oryzacystatin I of rice. Moreover, the purified protein proved capable of inhibiting the growth of the filamentous fungus Trichoderma reesei, suggesting that it can also be employed to inhibit the growth of pathogenic sugarcane fungi.
植物拥有多种抵御病原体攻击的防御机制。其中一种防御机制是利用蛋白酶抑制剂蛋白，这些蛋白会干扰病原体的发育和生长。甘蔗的生产力会受到植株对真菌病害易感性的影响，而真菌病害会导致产量损失。因此，一个相关的研究方向是探究植物利用半胱氨酸蛋白酶抑制剂（即特异性抑制半胱氨酸蛋白酶的蛋白）来控制植物病原体的天然防御机制。在本文中，我们讨论了一种甘蔗半胱氨酸蛋白酶抑制剂在大肠杆菌中的表达、纯化、抗真菌活性以及用于监测正确折叠的圆二色性。这些研究揭示了其二级结构与水稻的水稻半胱氨酸蛋白酶抑制剂I相似。此外，纯化后的蛋白被证明能够抑制丝状真菌里氏木霉的生长，这表明它也可用于抑制甘蔗致病真菌的生长。
