Biochemical Characterization of Proline Racemases from the Human Protozoan Parasite Trypanosoma cruzi and Definition of Putative Protein Signatures

Abstract

Proline racemase catalyzes the interconversion of Land D-proline enantiomers and has to date been described in only two species. Originally found in the bacterium Clostridium sticklandii, it contains cysteine residues in the active site and does not require co-factors or other known coenzymes. We recently described the first eukaryotic amino acid (proline) racemase, after isola-

Role of Δ1-Pyrroline-5-Carboxylate Dehydrogenase Supports Mitochondrial Metabolism and Host-Cell Invasion of Trypanosoma cruzi

“…In a comprehensive proteomic analysis of the T. cruzi secretome, proline-related enzymes have been described (92). Proline racemase converts D-proline into L-proline and acts as a host B-cell mitogen (93). The prolyl oligopeptidase hydrolyzes large substrates such as fibronectin and native collagen, which can fulfill proline requirements within the extracellular matrix during the mammal host cell invasion process (94).…”

Genetic Immunization Converts theTrypanosoma cruziB-Cell Mitogen Proline Racemase to an Effective Immunogen

“…Full-length TcPRACA was cloned from T. cruzi strain Y parasites, and the predicted amino acid sequence was Ͼ99% identical to the reported TcPRACA primary protein sequence from the CL strain (9). TcPRACA (rTcPRAC) was subcloned into a prokaryotic expression vector, and the purified rTcPRAC yielded the expected 45-kDa monomeric protein with minimal background protein contamination (Fig.…”

“…TcPRACB has been found in the cytoplasm of insect-stage epimastigotes. TcPRACA is expressed and released by infectious trypomastigotes and differs from TcPRACB by several point mutations and an aminoterminal secretion signal (8,9). TcPRACA isolated from the culture supernatant of infectious trypomastigotes and recombinant TcPRAC (rTcPRAC) were shown to induce nonspecific in vitro proliferation of T-cell-depleted or athymic murine splenocytes (45), but the effect of TcPRACA on the activation and function of specific B-cell subsets has not been determined.…”

“…cruzi proline racemase (TcPRAC) has been identified as a T-cell-independent (TI) B-cell mitogen (9,44,45). TcPRAC is a dimeric protein encoded by two paralogous genes per haploid genome: TcPRACA and TcPRACB.…”

NADH desidrogenase mitocondrial de Trypanosoma cruzi: subunidade 7 para diagnóstico diferencial de isolados humanos e análise funcional.

“…Deve-se ressaltar que T. cruzi (mas não Leishmania e T. brucei) expressa uma prolina racemase que permite utilizar, além de L-prolina, D-prolina (CHAMOND et al, 2003;ATWOOD et al, 2005).…”