A plastidial lysophosphatidic acid acyltransferase from oilseed rape.
The biosynthesis of phosphatidic acid, a key intermediate in the biosynthesis of lipids, is controlled by lysophosphatidic acid (LPA, or 1-acyl-glycerol-3-P) acyltransferase (LPAAT, EC 2.3.1.51). We have isolated a cDNA encoding a novel LPAAT by functional complementation of the Escherichia coli mutant plsC with an immature embryo cDNA library of oilseed rape (Brassica napus). Transformation of the acyltransferase-deficient E. coli strain JC201 with the cDNA sequence BAT2 alleviated the temperature-sensitive phenotype of the plsC mutant and conferred a palmitoyl-coenzyme A-preferring acyltransferase activity to membrane fractions. The BAT2 cDNA encoded a protein of 351 amino acids with a predicted molecular mass of 38 kD and an isoelectric point of 9.7. Chloroplast-import experiments showed processing of a BAT2 precursor protein to a mature protein of approximately 32 kD, which was localized in the membrane fraction. BAT2 is encoded by a minimum of two genes that may be expressed ubiquitously. These data are consistent with the identity of BAT2 as the plastidial enzyme of the prokaryotic glycerol-3-P pathway that uses a palmitoyl-ACP to produce phosphatidic acid with a prokaryotic-type acyl composition. The homologies between the deduced protein sequence of BAT2 with prokaryotic and eukaryotic microsomal LAP acytransferases suggest that seed microsomal forms may have evolved from the plastidial enzyme.
Laboratoire Physiologie Cellulaire et Moléculaire, Université Pierre et Marie Curie, Centre National de la Recherche Scientifique Unite Mixte de Recherche 7632, Tour 53, 4 Place Jussieu, 75252 Paris, France.
F
F
Bourgis
J C
JC
Kader
P
P
Barret
M
M
Renard
D
D
Robinson
C
C
Robinson
M
M
Delseny
T J
TJ
Roscoe
D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; D000217:Acyltransferases / Q000235:genetics / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D001937:Brassica / Q000201:enzymology* / Q000235:genetics; D002874:Chromosome Mapping; D018076:DNA, Complementary; D018744:DNA, Plant; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D010712:Phosphatidic Acids / Q000096:biosynthesis; D018087:Plastids / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D018744:DNA, Plant; D029968:Escherichia coli Proteins; D010712:Phosphatidic Acids; D000217:Acyltransferases; D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; C495091:plsC protein, E coli