Batista I F, Nonato M C, Bonfadini M R, Beltramini L M, Oliva M L, Sampaio M U, Sampaio C A, Garratt R C
Departamento de Bioquímica, Universidade Federal de São Paulo (UNIFESP/EPM), Rua Três de Maio 100, CEP 04044-020 Sao Paulo SP, Brazil.
Acta Crystallogr D Biol Crystallogr. 2001 Apr;57(Pt 4):602-4. doi: 10.1107/s0907444901001810.
Enterolobium contortisiliquum trypsin inhibitor (EcTI) belongs to the Kunitz family of plant inhibitors, which are widely distributed in nature, especially in plant seeds. EcTI is composed of two polypeptide chains with a total of 174 residues, homologous to other inhibitors from the same family. EcTI crystals, which were obtained with the acupuncture-gel technique, diffract to 2.0 A resolution and belong to space group P2(1), with unit-cell parameters a = 37.12, b = 38.42, c = 54.08 A, beta = 98.08 degrees. Molecular-replacement techniques using Erythrina caffra trypsin inhibitor (PDB code 1tie) as the search model indicate one monomer in the asymmetric unit. The secondary-structure content of EcTI was determined by circular dichroism spectroscopy, yielding values compatible with the expected topology.
扭序决明胰蛋白酶抑制剂（EcTI）属于植物抑制剂的Kunitz家族，该家族在自然界广泛分布，尤其是在植物种子中。EcTI由两条多肽链组成，共174个残基，与同一家族的其他抑制剂同源。通过针刺凝胶技术获得的EcTI晶体，其衍射分辨率为2.0 Å，属于空间群P2(1)，晶胞参数为a = 37.12，b = 38.42，c = 54.08 Å，β = 98.08°。以刺桐胰蛋白酶抑制剂（PDB代码1tie）作为搜索模型的分子置换技术表明，不对称单元中有一个单体。通过圆二色光谱法测定了EcTI的二级结构含量，得到的值与预期拓扑结构相符。
