Trypanosoma cruzi cDNA encodes a tandemly repeated domain structure characteristic of small stress proteins and glutathione S-transferases.
The isolation, characterization, and expression of a novel cDNA encoding a Trypanosoma cruzi polypeptide (TcAc2), homologous to various small stress proteins and glutathione S-transferases, are described. The deduced amino-acid sequence revealed two domains sharing 27% identity and an additional 27% similarity to each other suggesting that the molecule may have evolved from a single domain by a process of gene duplication and fusion. The TcAc2 cDNA was subcloned into the pGEX-2T vector for expression in E coli. In vitro translation products of epimastigote mRNA, immunoprecipitated with anti-TXepi serum, showed a major radioactive band of 52 kDa. Immunoprecipitation of [35S]methionine labelled epimastigote and trypomastigote antigens after pulse chase experiments, using anti-TcAc2 fusion protein antibodies, showed that the protein is released into the culture medium. Moreover, Western blot analysis revealed a single band of 52 kDa with epimastigote, trypomastigote and amastigote antigens. Primary structure homology searches revealed that each TcAc2 domain contained within its N-terminus significant homology to Solanum tuberosum pathogenesis-related protein PR1, soybean heat shock protein 26-A, auxin regulated clone pCNT103 from Nicotiana tabacum and Drosophila melanogaster glutathione S-transferase 27 (GST27). This finding was supported by a comparison of hydrophobicity profiles of TcAc2 and these proteins. Most of them play a central role in protection mechanisms against stress. Based on the homology between TcAc2, glutathione S-transferases (GST) and small stress proteins, it is likely that the TcAc2 gene product may play a crucial role in parasite's adaptation to its microenvironment. These molecules could be considered as members of the GST superfamily, where the T cruzi protein may take a particular place because of its internal gene duplication.
Schöneck
R
R
Research Laboratory on Trypanosomatids, INSERM U415, Lille, France.
Plumas-Marty
B
B
Taibi
A
A
Billaut-Mulot
O
O
Loyens
M
M
Gras-Masse
H
H
Capron
A
A
Ouaissi
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D017931:DNA Primers; D015342:DNA Probes; D018076:DNA, Complementary; D016054:DNA, Protozoan / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D004926:Escherichia coli; D015723:Gene Library; D005982:Glutathione Transferase / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D010944:Plants / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013462:Sulfur Radioisotopes; D014349:Trypanosoma cruzi / Q000235:genetics*
D017931:DNA Primers; D015342:DNA Probes; D018076:DNA, Complementary; D016054:DNA, Protozoan; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D013462:Sulfur Radioisotopes; D008715:Methionine; D005982:Glutathione Transferase