Cazzulo J J, Martínez J, Parodi A J, Wernstedt C, Hellman U
Instituto de Investigaciones Bioquímicas Luis F. Leloir, Fundación Campomar-CONICET-Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
FEMS Microbiol Lett. 1992 Dec 15;100(1-3):411-6. doi: 10.1111/j.1574-6968.1992.tb14070.x.
Cruzipain, the major cysteine proteinase from Trypanosoma cruzi, has a 130 amino acid-long C-terminal domain, which, although microheterogeneous in SDS-PAGE, has a single N-terminal amino acid sequence. Most of the Thr residues present at the beginning of this sequence are modified; the nature of this modification is still unknown, but O-glycosylation and phosphorylation seem both to be absent. The only potential site for N-glycosylation (Asn 254) is glycosylated in vivo. Most of the eight Cys residues are involved in disulfide bridges. The results are consistent with cruzipain being made of two well-defined domains, a catalytic one with high homology to cathepsin L, and a C-terminal domain, linked to the former by a 'hinge' corresponding to the Pro- and Thr-rich region at its N-terminus.
克氏锥虫蛋白酶是克氏锥虫的主要半胱氨酸蛋白酶，其C端结构域由130个氨基酸组成，尽管在SDS-PAGE中存在微不均一性，但其N端氨基酸序列是单一的。该序列起始处的大多数苏氨酸残基都被修饰；这种修饰的性质仍然未知，但似乎既不存在O-糖基化也不存在磷酸化。唯一潜在的N-糖基化位点（Asn 254）在体内被糖基化。八个半胱氨酸残基中的大多数都参与了二硫键的形成。结果表明，克氏锥虫蛋白酶由两个明确的结构域组成，一个与组织蛋白酶L具有高度同源性的催化结构域，以及一个通过对应于其N端富含脯氨酸和苏氨酸区域的“铰链”与前者相连的C端结构域。
