de Matos Guedes Herbert Leonel, Carneiro Monique Pacheco Duarte, Gomes Daniel Cláudio de Oliveira, Rossi-Bergmanmn Bartira, Giovanni de Simone Salvatore
Laboratório de Bioquímica de Proteínas e Peptídeos, Departamento de Bioquímica e Biologia Molecular, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
Parasitol Res. 2007 Sep;101(4):853-63. doi: 10.1007/s00436-007-0552-5. Epub 2007 May 27.
Serine oligopeptidases of trypanosomatids are emerging as important virulence factors and therapeutic targets in trypanosome infections. A complete open reading frame of oligopeptidase B from Leishmania amazonensis was amplified with polymerase chain reaction with gradient annealing temperatures using primers designed for the oligopeptidase B gene from L. major. The 2,196-bp fragment coded for a protein of 731 amino acids with a predicted molecular mass of 83.49 KDa. The encoded protein (La_OpB) shares a 90% identity with oligopeptidases of L. major and L. infantum, 84% with L. braziliensis, and approximately 62 identity with Trypanosoma peptidases. The oligopeptidase B gene is expressed in all cycle stages of L. amazonensis. The three dimensional model of La_OpB was obtained by homology modeling based on the structure of prolyl oligopeptidases. We mapped a La_OpB model that presents a greater negative charge than prolyl oligopeptidases; our results suggest a difference in the S2 subsite when compared to oligopeptidases B from Trypanosoma and bacterial oligopeptidases B. The La_OpB model serves as a starting point for its exploration as a potential target source for a rational chemotherapy.
锥虫的丝氨酸寡肽酶正逐渐成为锥虫感染中重要的毒力因子和治疗靶点。使用针对硕大利什曼原虫寡肽酶B基因设计的引物，通过梯度退火温度的聚合酶链反应扩增了亚马逊利什曼原虫寡肽酶B的完整开放阅读框。这个2196碱基对的片段编码了一个731个氨基酸的蛋白质，预测分子量为83.49千道尔顿。编码的蛋白质（La_OpB）与硕大利什曼原虫和婴儿利什曼原虫的寡肽酶有90%的同一性，与巴西利什曼原虫有84%的同一性，与锥虫肽酶大约有62%的同一性。寡肽酶B基因在亚马逊利什曼原虫的所有周期阶段都有表达。基于脯氨酰寡肽酶的结构，通过同源建模获得了La_OpB的三维模型。我们绘制了一个La_OpB模型，该模型比脯氨酰寡肽酶呈现出更大的负电荷；我们的结果表明，与锥虫的寡肽酶B和细菌寡肽酶B相比，其S2亚位点存在差异。La_OpB模型为将其作为合理化疗的潜在靶点来源进行探索提供了一个起点。
