Carreras Esther, Boix Ester, Navarro Susanna, Rosenberg Helene F, Cuchillo Claudi M, Nogués M Victòria
Departament de Bioquímica i Biologia Molecular, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain.
Mol Cell Biochem. 2005 Apr;272(1-2):1-7. doi: 10.1007/s11010-005-4777-2.
Eosinophil cationic protein (ECP) is a ribonuclease secreted from activated eosinophils that may cause tissue injure as a result of eosinophilic inflammation. ECP possesses bactericidal, antiviral and helminthotoxic activity and inhibits mammalian cell growth. The mechanism by which ECP exerts its toxicity is not known but it has been related to the ability of the protein to destabilise lipid bilayers. We have assessed the involvement of some cationic and aromatic surface exposed residues of ECP in the inhibition of proliferation of mammalian cell lines. We have constructed ECP mutants for the selected residues and assessed their ability to prevent cell growth. Trp10 and Trp35 together with the adjacent stacking residue are critical for the damaging effect of ECP on mammalian cell lines. These residues are also crucial for the membrane disruption activity of ECP. Other exposed aromatic residues packed against arginines (Arg75-Phe76 and Arg121-Tyr122) and specific cationic amino acids (Arg101 and Arg104) of ECP play a secondary role in the cell growth inhibition. This may be related to the ability of the protein to bind carbohydrates such as those found on the surface of mammalian cells.
嗜酸性粒细胞阳离子蛋白（ECP）是一种由活化的嗜酸性粒细胞分泌的核糖核酸酶，嗜酸性粒细胞炎症可能导致组织损伤。ECP具有杀菌、抗病毒和抗蠕虫毒性活性，并能抑制哺乳动物细胞生长。ECP发挥其毒性的机制尚不清楚，但这与该蛋白破坏脂质双层的能力有关。我们评估了ECP一些暴露于表面的阳离子和芳香族残基在抑制哺乳动物细胞系增殖中的作用。我们构建了所选残基的ECP突变体，并评估了它们阻止细胞生长的能力。色氨酸10和色氨酸35以及相邻的堆积残基对于ECP对哺乳动物细胞系的破坏作用至关重要。这些残基对于ECP的膜破坏活性也至关重要。ECP中其他与精氨酸堆积的暴露芳香族残基（精氨酸75-苯丙氨酸76和精氨酸121-酪氨酸122）以及特定的阳离子氨基酸（精氨酸101和精氨酸104）在细胞生长抑制中起次要作用。这可能与该蛋白结合碳水化合物（如在哺乳动物细胞表面发现的那些）的能力有关。
