RESUMO

Trypanosomatids cause deadly diseases in humans. Of the various biochemical pathways in trypanosomatids, glycolysis, has received special attention because of being sequestered in peroxisome like organelles critical for the survival of the parasites. This study focuses on phosphoglycerate kinase (PGK) from Leishmania spp. which, exists in two isoforms, the cytoplasmic PGKB and glycosomal PGKC differing in their biochemical properties. Computational analysis predicted the likelihood of a transmembrane helix only in the glycosomal isoform PGKC, of approximate length 20 residues in the 62-residue extension, ending at, arginine residues R471 and R472. From experimental studies using circular dichroism and NMR with deuterated sodium dodecyl sulfate, we find that the transmembrane helix spans residues 448±2 to 476 in Leishmania mexicana PGKC. The significance of this observation is discussed in the context of glycosomal transport and substrate tunneling.

Assuntos

Leishmania mexicana/enzimologia , Peptídeos/química , Fosfoglicerato Quinase/química , Proteínas de Protozoários/química , Sequência de Aminoácidos , Dicroísmo Circular , Biologia Computacional , Citoplasma/enzimologia , Citoplasma/genética , Isoenzimas/química , Isoenzimas/genética , Leishmania mexicana/genética , Espectroscopia de Ressonância Magnética , Proteínas de Membrana/química , Micelas , Microcorpos/enzimologia , Microcorpos/genética , Dados de Sequência Molecular , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Transporte Proteico , Solubilidade , Especificidade por Substrato