A pantothenate derivative is covalently bound to mitochondrial proteins in Neurospora crassa.
The presence of protein-bound pantothenate in Neurospora crassa was investigated by labelling a pantothenate auxotroph (pan-2) with [14C]pantothenate and examining mycelial homogenates on dodecyl sulfate/polyacrylamide gels. Five peaks of radioactivity were found, with apparent molecular masses of 200, 140, 22, 19, and 9 kDa. The 200-kDa peak was identified as fatty acid synthetase, based on its absence in a fatty acid synthetase mutant. The 22-kDa and 19-kDa peaks co-purified with mitochondrial markers on sucrose gradients. When purified mitochondria were fractionated, the 19-kDa protein was associated with the inner membrane and the 22-kDa protein was enriched in the soluble mitochondrial fraction. The label was quantitatively recovered from the mitochondrial proteins as 4'-phosphopantetheine after mild alkaline hydrolysis. Although the function of this post-translational modification of mitochondrial proteins is not known, several possibilities are discussed: the 4'-phosphopantetheine may act as a carrier group in an enzymatic reaction, or it may perform a regulatory function as part of an enzyme complex.
Lakin-Thomas
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Brody
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D002499:Centrifugation, Density Gradient; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000378:metabolism*; D006868:Hydrolysis; D008928:Mitochondria / Q000378:metabolism*; D008970:Molecular Weight; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000378:metabolism*; D010205:Pantothenic Acid / Q000378:metabolism*; D011485:Protein Binding
D005656:Fungal Proteins; D010205:Pantothenic Acid