In the current study, a novel putative protein of Leishmania donovani, amastin-like surface protein (ALSP) has been characterized. The gene was cloned in a bacterial system and the protein was overexpressed. A polyclonal antibody was developed against the protein, which detected a 10 kDa band in the L. donovani amastigote. ALSP mRNA was detected in L. donovani amastigote, which was not expressed in the promastigote. ALSP mRNA was not expressed in either morphological forms of Leishmania major. MALDI-TOF confirmed the molecular weight of ALSP as 10 kDa. I-TASSER predicted the function of ALSP as a lipase, which was confirmed by preliminary in-vitro experiments using amastigotes of L. donovani. ALSP has GAS amino acid sequences, which might act as the active site for its lipase activity. The selective expression of ALSP in amastigotes probably makes it important in virulence mechanisms such as survival in the phagolysosome and modulation of its membrane and other metabolic functions, necessary for parasite survival in the human host. ALSP can act as a peptide vaccine target and maybe detected in the peripheral blood or urine as a molecular biomarker of active disease in visceral leishmaniasis.

中文翻译：

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一种可能的脂肪酶 Leishmania donovani 的新型 aastin 样表面蛋白 (ALSP) 的表征

在目前的研究中，一种新的Leishmania donovani假定蛋白质，amastin 样表面蛋白 (ALSP) 已被表征。该基因被克隆到细菌系统中，蛋白质被过度表达。开发了针对该蛋白质的多克隆抗体，该抗体在L. donovani无鞭毛体中检测到 10 kDa 条带。在L. donovani amastigote中检测到 ALSP mRNA ，但在前鞭毛体中不表达。ALSP mRNA 在两种主要利什曼原虫的形态中均未表达。MALDI-TOF 确认 ALSP 的分子量为 10 kDa。I-TASSER 预测了 ALSP 作为脂肪酶的功能，这已通过使用L. donovani的无鞭毛体的初步体外实验得到证实. ALSP 具有 GAS 氨基酸序列，可能作为其脂肪酶活性的活性位点。ALSP 在无鞭毛体中的选择性表达可能使其在毒力机制中变得重要，例如在吞噬溶酶体中的存活以及对其膜和其他代谢功能的调节，这是寄生虫在人类宿主中存活所必需的。ALSP 可以作为肽疫苗的靶标，并可能在外周血或尿液中检测到作为内脏利什曼病活动性疾病的分子生物标志物。