Highly specific methyl-end fatty-acid desaturases of trypanosomatids

Mol Biochem Parasitol. 2011 Feb;175(2):126-32. doi: 10.1016/j.molbiopara.2010.10.006. Epub 2010 Oct 23.

Abstract

A detailed analysis of the trypanosomatids' genome projects revealed the presence of genes predicted to encode fatty-acid desaturases of the methyl-end type (MED). After cloning and functional characterization of all identified genes, it can be concluded that Trypanosoma cruzi contains two MEDs with oleate desaturase (OD) activities whereas Leishmania major contains one OD and two active linoleate desaturases (LD). All characterized ODs are highly specific for oleate (18:1Δ9) as substrate, presenting a ν+3 regioselectivity, although palmitoleate (16:1Δ9) can be desaturated as well, but to a lesser extent. L. major LD appears to use exclusively linoleate (18:2n-6), converting it into α-linolenate (18:3n-3). This strong specificity assures no further conversion of polyunsaturated fatty acids (PUFAs) of the n-6 series into the n-3 series, downstream in the PUFA biosynthesis pathway. This characterization completes the identification of all enzymes involved in PUFA biosynthesis in a parasitic protist. Differently from their Trypanosoma brucei orthologue, T. cruzi and L. major ODs were more active when expressed either, in the presence of trienoic fatty acids or at higher temperatures. This could be evidence for a differential post-translational regulation of these enzymes as a result of direct sensing of environmentally dependent parameters such as membrane fluidity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • DNA, Protozoan / chemistry
  • DNA, Protozoan / genetics
  • Fatty Acid Desaturases / genetics
  • Fatty Acid Desaturases / isolation & purification
  • Fatty Acid Desaturases / metabolism*
  • Kinetics
  • Leishmania major / enzymology*
  • Linoleic Acid / metabolism
  • Molecular Sequence Data
  • Oleic Acid / metabolism
  • Palmitates / metabolism
  • Phylogeny
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Temperature
  • Trypanosoma brucei brucei / enzymology*
  • Trypanosoma cruzi / enzymology*

Substances

  • DNA, Protozoan
  • Palmitates
  • Recombinant Proteins
  • Oleic Acid
  • Linoleic Acid
  • Fatty Acid Desaturases

Associated data

  • GENBANK/CAJ02312
  • GENBANK/CAJ03117
  • GENBANK/CAJ06920