l-Asparagine synthetase (AS) acts in asparagine formation and can be classified into two families: AS-A or AS-B. AS-A is mainly found in prokaryotes and can synthetize asparagine from ammonia. Distinct from other eukaryotes, Trypanosoma cruzi produces an AS-A. AS-A from Trypanosoma cruzi (Tc-AS-A) differs from prokaryotic AS-A due to its ability to catalyze asparagine synthesis using both glutamine and ammonia as nitrogen sources. Regarding these peculiarities, this work uses several biophysical techniques to provide data concerning the Tc-AS-A in-solution behavior. Tc-AS-A was produced as a recombinant and purified by three chromatography steps. Circular dichroism, dynamic light scattering, and analytical size exclusion chromatography showed that Tc-AS-A has the same fold and quaternary arrangement of prokaryotic AS-A. Despite the tendency of protein to aggregate, stable dimers were obtained when solubilization occurred at pH ≤ 7.0. We also demonstrate the protective efficacy against T. cruzi infection in mice immunized with Tc-AS-A. Our results indicate that immunization with Tc-AS-A might confer partial protection to infective forms of T. cruzi in this particular model.

1-天冬酰胺合成酶（AS）在天冬酰胺形成中起作用，并且可以分为两个家族：AS-A或AS-B。AS-A主要存在于原核生物中，可以从氨中合成天冬酰胺。与其他真核生物不同，克氏锥虫产生AS-A。锥虫的AS-Ai（Tc-AS-A）与原核AS-A不同，因为它使用谷氨酰胺和氨作为氮源催化天冬酰胺合成的能力。关于这些特性，这项工作使用了几种生物物理技术来提供有关Tc-AS-A溶液内行为的数据。Tc-AS-A以重组形式生产，并通过三个色谱步骤纯化。圆二色性，动态光散射和分析尺寸排阻色谱法表明，Tc-AS-A具有与原核AS-A相同的折叠和四级排列。尽管有蛋白质聚集的趋势，但当在pH≤7.0时发生增溶时，可获得稳定的二聚体。我们还证明了对克鲁斯锥虫的保护作用用Tc-AS-A免疫的小鼠体内感染。我们的结果表明，在此特定模型中，用Tc-AS-A进行免疫可能会赋予克氏锥虫感染性形式部分保护。