Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Ceará 60451-970, Brazil.
Biopolymers. 2012;98(4):406-15. doi: 10.1002/bip.22068.
A thermostable chitin-binding protein (14.3 kDa) with antifungal activity was isolated from Moringa oleifera seeds by affinity chromatography on chitin followed by ion exchange chromatography. NH(2-) CPAIQRCCQQLRNIQPPCRCCQ (Mo-CBP3) is a glycoprotein with 2.5% sugar, pI 10.8, without hemagglutination, chitinase or beta-glucanase activities. Mo-CBP3 possesses in vitro antifungal activity against the phytopathogenicfungi Fusarium solani, F. oxysporum, Colletotrichum musae and C. gloesporioides. Contrarily, Mo-CBP3 did not affect Pythium oligandrum, an oomycete. At 0.05 mg/ml, Mo-CBP3 showed to be fungistatic against F. solani, but at 0.1 mg/ml Mo-CBP3 behaved as a potent fungicidal agent as it inhibited both the spore germination and mycelial growth of F. solani. Surprisingly, the effect of Mo-CBP3 against spore germination was observed even when the protein was heated at 100 degrees C for 1 h or pretreated with 0.15M N-acetyl-D-glucosamine. Mo-CBP3 inhibited the glucose-stimulated acidification of the incubation medium by F. solani. This is apparently caused by structural plasma membrane disarrangement induced by Mo-CBP3. Altogether, these results suggest that Mo-CBP3 might be involved in plant defense mechanisms and could be used as potential antifungal agent for controlling fungal pathogens in plants.
从辣木种子中通过亲和层析（chitin）和离子交换层析分离到一种热稳定的几丁质结合蛋白（14.3 kDa），具有抗真菌活性。NH2-CPAIQRCCQQLRNIQPPCRCCQ（Mo-CBP3）是一种糖蛋白，含糖量为 2.5%，无血凝、几丁质酶或β-葡聚糖酶活性。Mo-CBP3 对植物病原真菌茄腐镰刀菌、尖孢镰刀菌、香蕉炭疽菌和胶孢炭疽菌具有体外抗真菌活性。相反，Mo-CBP3 对卵菌纲真菌腐霉属没有影响。在 0.05 mg/ml 时，Mo-CBP3 对茄腐镰刀菌表现出抑菌作用，但在 0.1 mg/ml 时，Mo-CBP3 表现出强烈的杀菌作用，因为它抑制了茄腐镰刀菌的孢子萌发和菌丝生长。令人惊讶的是，即使将 Mo-CBP3 在 100°C 下加热 1 小时或用 0.15M N-乙酰-D-葡萄糖胺预处理，Mo-CBP3 对孢子萌发的抑制作用仍能观察到。Mo-CBP3 抑制了茄腐镰刀菌对葡萄糖刺激的培养液酸化。这显然是由 Mo-CBP3 引起的质膜结构紊乱造成的。总的来说，这些结果表明，Mo-CBP3 可能参与植物防御机制，并可作为控制植物真菌病原体的潜在抗真菌剂。
