Neurospora mitochondria contain an acyl-carrier protein

Mitochondria of Neurospora crassa were found to contain a protein which was labelled with [14C]pantothenic acid and which carried an acyl group. This protein, when purified 6000-fold, closely resembled the bacterial and chloroplast acyl-carrier protein(s) [ACP(s)] in its physical and chemical properties. The predominant acyl group esterified to the purified protein was 3-hydroxytetradecanoate, as determined by gas chromatographic mass spectrometry. The amino acid sequence of the tryptic peptide carrying the 4'-phosphophantetheine moiety showed a high degree of sequence similarity to the analogous bacterial and chloroplast ACP peptide sequences. The possible functions of this ACP in lipid metabolism are discussed in view of the fact that Neurospora has a separate cytoplasmic enzyme complex which carries out the de novo biosynthesis of fatty acids.