Disease relevance of Phosphopantetheine

• The factor has now been purified to apparent homogeneity and has been found to be identical to acyl carrier protein (ACP), the phosphopantetheine-containing protein of low molecular weight that has long been known to be essential for fatty acid synthesis in E. coli and other organisms [1].
• Mycobacterium tuberculosis contains >20 enzymes that require activation by transfer of the 4'-phosphopantetheine moiety of CoA onto a conserved serine residue, a posttranslational modification catalyzed by 4'-phosphopantetheinyl transferases (PPTases) [2].
• 4'-phosphopantetheine transfer in primary and secondary metabolism of Bacillus subtilis [3].
• Orf* contains the consensus sequence, DSLD, for attachment of 4'-phosphopantetheine [4].
• On the 4'-phosphopantetheine content of chicken and rat liver fatty acid synthetases [5].

High impact information on Phosphopantetheine

• The crystal structure of the AHL synthase, EsaI, determined at 1.8 A resolution, reveals a remarkable structural similarity to the N-acetyltransferases and defines a common phosphopantetheine binding fold as the catalytic core [6].
• Superposition of bound adenylyl moieties from dPCoA in PPAT and ATP in aminoacyl-tRNA synthetases suggests nucleophilic attack by the 4'-phosphopantetheine on the alpha-phosphate of ATP [7].
• Acyl carrier protein (ACP) import into chloroplasts does not require the phosphopantetheine: evidence for a chloroplast holo-ACP synthase [8].
• Structural comparison of LipB with lipoate protein ligase A indicates that, despite conserved structural and sequence active-site features in the two enzymes, 4'-phosphopantetheine-bound octanoic acid recognition is a specific property of LipB [9].
• This distance is too large to be covered simply by alternative positioning of a statically anchored, fully extended phosphopantetheine arm of the acyl carrier protein domain from module 5 [10].

Chemical compound and disease context of Phosphopantetheine

• Several properties of the mitochondrial protein were similar to the Escherichia coli acyl carrier protein: Mr on sodium dodecyl sulfate gels, decreased electrophoretic mobility under deacylating conditions, isoelectric point, and covalent attachment of 4'-phosphopantetheine [11].
• Mass spectrometry of purified active Orf* confirmed the presence of 4'-phosphopantetheine and 27-hydroxyoctacosanoic acid in the major species [4].
• Pantothenate (vitamin B5) is the precursor for the biosynthesis of the phosphopantetheine moiety of coenzyme A and acyl carrier protein, and is synthesised in Escherichia coli by four enzymic reactions [12].
• Biosynthesis of the Escherichia coli siderophore enterobactin: sequence of the entF gene, expression and purification of EntF, and analysis of covalent phosphopantetheine [13].
• In E. coli, TycA was labeled with beta-[3H]alanine, a precursor of 4'-phosphopantetheine, indicating that TycA is modified with a beta-alanine-containing cofactor [14].

Biological context of Phosphopantetheine

• We demonstrate that AtHAL3a catalyzes the decarboxylation of (R)-4'-phospho-N-pantothenoylcysteine to 4'-phosphopantetheine [15].
• The products of CoA hydrolysis were 3'-phosphoadenosine 5'-monophosphate and 4'-phosphopantetheine [16].
• A single candidate 4'-phosphopantetheine transferase, identified by BLAST searches of the human genome sequence data base, has been cloned, expressed, and characterized [17].
• No significant energy transfer occurs between sites on different polypeptide chains so that the distances must be greater than 55 A. The distance between the serine on the thioesterase and the 4'-phosphopantetheine on the same polypeptide is 48 A; again no interpolypeptide chain energy transfer was observed [18].
• In the low salt conformer, the phosphopantetheine and cysteine SH groups are juxtaposed, and the DTNB reaction (k2 approximately 132 mM-1 S-1) and dimerization are both facilitated [19].

Anatomical context of Phosphopantetheine

• The iniB gene has homology to cell wall proteins, and iniA contains a phosphopantetheine attachment site motif suggestive of an acyl carrier protein [20].
• Neurospora crassa mitochondria contain two forms of a 4'-phosphopantetheine-modified protein [11].
• The fatty acid synthetase from lactating rat mammary gland is shown to consist of two polyfunctional polypeptides of similar molecular weight (about 220,000); a 4'-phosphopantetheine residue is covalently bound to one, or both subunits [21].

Associations of Phosphopantetheine with other chemical compounds

• These results strongly support the conclusion that there is a holo-ACP synthase in the soluble compartment of the chloroplast capable of transferring the phosphopantetheine of coenzyme A to ACP [8].
• We have recently identified cDNA for CoA synthase and demonstrated that it encodes a bifunctional enzyme possessing 4'-phosphopantetheine adenylyltransferase and dephospho-CoA kinase activities [22].
• Dfp proteins are bifunctional enzymes catalyzing the synthesis of 4'-phosphopantothenoylcysteine (CoaB activity) and its decarboxylation to 4'-phosphopantetheine (CoaC activity) [23].
• The 4'-phosphopantetheine hydrolase of rat liver, partially purified by ammonium sulfate precipitation, catalyzes the hydrolysis of the prosthetic group 4'-phosphopantetheine from the holo-fatty acid synthetase [24].
• The flavoprotein Dfp catalyzes the synthesis of the coenzyme A precursor 4'-phosphopantetheine in the presence of 4'-phosphopantothenate, cysteine, CTP, and Mg(2+) (Strauss, E., Kinsland, C., Ge, Y., McLafferty, F. W., and Begley, T. P. (2001) J. Biol. Chem. 276, 13513-13516) [25].

Gene context of Phosphopantetheine

• All the partial activities of human FAS are comparable to those of other animal FASs, except for the beta-ketoacyl synthase, whose significantly lower activity is attributable to the low 4'-phosphopantetheine content of HepG2 FAS [26].
• The HAL3A gene encodes a 4'-phosphopantothenoyl-cysteine decarboxilase that generates 4'-phosphopantetheine [27].
• The structural difference between F-ACP and ACP persisted after the removal of the 4'-phosphopantetheine prosthetic group, and both forms of the protein had identical properties in an in vitro fatty acid synthase assay [28].
• Activation of FAS-A to its holoform was achieved by transformation with a second B. ammoniagenes gene, PPT1, encoding a type-I FAS-specific phosphopantetheine transferase [29].
• The acyl carrier protein with its prosthetic 4'-phosphopantetheine group is located within a single exon supporting the idea that rat FAS has evolved by gene fusion [30].

Analytical, diagnostic and therapeutic context of Phosphopantetheine

• The presence of intrinsic phosphopantetheine adenylyltransferase activity was further confirmed by site-directed mutagenesis [31].
• The resultant apo-fatty acid synthetase was quantitated by immunoprecipitation and it was also converted to the holoprotein with a crude preparation of rat liver 4'-phosphopantetheine transferase [24].
• Based on sequence analysis, the translated protein had a pI of 4.3, an alpha-helical structure, and a phosphopantetheine binding motif [32].
• MALDI analysis of the tryptic fragments revealed that in the recombinant TY1 the putative 4'-phosphopantetheine binding site (562Ser) is not modified by the cofactor [33].
• E. coli provides a tremendous potential for genetic engineering and was manipulated in our study by stable chromosomal integration of the 4'-phosphopantetheine transferase gene sfp to ensure heterologous production of fully active holoenzmyes [34].

References