Cloning and heterologous expression of a broad specificity aminotransferase of Leishmania mexicana promastigotes1.
We have previously reported that Leishmania mexicana promastigotes possess a broad substrate specificity aminotransferase (BSAT), able to transaminate aspartate, aromatic amino acids, methionine and leucine. We have confirmed now this unusual substrate specificity by cloning its gene and expressing in Escherichia coli the recombinant active protein. The amino acid sequence of BSAT shares over 40% identity with other eukaryotic and prokaryotic aspartate aminotransferases, thus showing that the enzyme belongs to the subfamily Ialpha of aminotransferases, and has only 6% identity with the tyrosine aminotransferase from Trypanosoma cruzi, which has a similar substrate specificity. The production of recombinant active enzyme in good yields opens up the possibility of obtaining its 3D-structure, in order to investigate the structural basis of the broad substrate specificity.
Vernal
Javier
J
Instituto de Química y Fisicoquímica Biológica IQUIFIB-CONICET, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, CP1113 Buenos Aires, Argentina.
José Cazzulo
Juan
J
Nowicki
Cristina
C
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D015870:Gene Expression; D007894:Leishmania mexicana / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D010957:Plasmids; D011994:Recombinant Proteins / Q000235:genetics; D013379:Substrate Specificity; D000637:Transaminases / Q000235:genetics* / Q000378:metabolism
D011994:Recombinant Proteins; D000637:Transaminases