A novel glycosylphosphatidylinositol in African trypanosomes: A possible catabolic intermediate

Kenneth G. Milne, Michael A J Ferguson, Paul T. Englund

Research output: Contribution to journalArticle

Abstract

The major glycosylphosphatidylinositols (GPIs) in African trypanosomes are glycolipid A, the precursor of the variant surface glycoprotein membrane anchor, and glycolipid C, a species identical to glycolipid A except that it contains an acylated inositol. Both glycolipids A and C contain dimyristoyl glycerol and are efficiently labeled with [3H]myristate in a cell-free system. We now report a novel GPI known as lipid X. This GPI is radiolabeled strongly with [3H]palmitate (and very poorly with [3H]myristate or [3H]stearate) in digitonin-permeabilized cells. The structure of lipid X is Man1GlcNAc-(2-O-palmitoyl)-D-myo-inositol-1-HPO4-3(lyso-palmitoylglycerol). Metabolically, lipid X exists as an intermediate, and can be detected only under conditions in which its formation is stimulated (e.g. by EDTA) or its breakdown is inhibited (e.g. by Co2+). Lipid X has not been observed previously because these conditions do not support GPI biosynthesis. We speculate that lipid X is an intermediate in the catabolism of conventional trypanosome GPIs, possibly deriving from breakdown of glycolipid C.

Original languageEnglish (US)
Pages (from-to)1465-1471
Number of pages7
JournalJournal of Biological Chemistry
Volume274
Issue number3
DOIs
StatePublished - Jan 15 1999

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Glycosylphosphatidylinositols
Trypanosomiasis
Glycolipids
Myristic Acid
Inositol
Stearates
Digitonin
Cell-Free System
Palmitates
Biosynthesis
Membrane Glycoproteins
Anchors
Edetic Acid
Glycerol
lipid X
Membranes

ASJC Scopus subject areas

  • Biochemistry

Cite this

A novel glycosylphosphatidylinositol in African trypanosomes : A possible catabolic intermediate. / Milne, Kenneth G.; Ferguson, Michael A J; Englund, Paul T.

In: Journal of Biological Chemistry, Vol. 274, No. 3, 15.01.1999, p. 1465-1471.

Research output: Contribution to journalArticle

Milne, Kenneth G. ; Ferguson, Michael A J ; Englund, Paul T. / A novel glycosylphosphatidylinositol in African trypanosomes : A possible catabolic intermediate. In: Journal of Biological Chemistry. 1999 ; Vol. 274, No. 3. pp. 1465-1471.
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