Crystal Structure of the Plant PPC Decarboxylase AtHAL3a Complexed with an Ene-thiol Reaction Intermediate

Steinbacher, Stefan; Hernández-Acosta, Pilar; Bieseler, Bastian; Blaesse, M.; Huber, Robert; Culiáñez-Macià, Francisco A.; Kupke, Thomas

doi:10.1016/s0022-2836(03)00092-5

Cited by 45 publications

(57 citation statements)

References 30 publications

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“…Therefore, an exciting possibility would be that the S. cerevisiae Hal3 (and possibly Vhs3) could act in the CoA biosynthetic pathway. However, molecular characterization of the AtHal3a catalytic mechanisms (14,33) has revealed a key role for Cys 175 , a residue that is not conserved in Hal3 or Vhs3. Therefore, a hypothetic role of Hal3 or Vhs3 in CoA biosynthesis in S. cerevisiae, which would explain the requirement for His 378 for function, seems unlikely.…”

Section: Discussionmentioning

confidence: 99%

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Functional Characterization of the Yeast Ppz1 Phosphatase Inhibitory Subunit Hal3

Muñoz

Ruiz

Marquina

et al. 2004

Journal of Biological Chemistry

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Section: Discussionmentioning

confidence: 99%

“…could catalyze the decarboxylation of 4Ј-phosphopantothenoylcysteine (13), suggesting that this protein could be involved in coenzyme A biosynthesis, and pointed out an important role of Cys 175 in the catalytic mechanism (13,14). It is worth noting that a such Cys residue is not conserved in yeast Hal3.…”

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confidence: 99%

Functional Characterization of the Yeast Ppz1 Phosphatase Inhibitory Subunit Hal3

Muñoz

Ruiz

Marquina

et al. 2004

Journal of Biological Chemistry

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“…The plant CoA biosynthetic pathway has been recently defined in plants , and the biochemistry of one of the biosynthetic enzymes, HAL3A (AtCoaC, PPCDC), has been studied in detail (Albert et al, 2000;Kupke et al, 2001;HernandezAcosta et al, 2002;Steinbacher et al, 2003). HAL3A is a flavoprotein that catalyzes the decarboxylation of PPC to 4#-phosphopantetheine (Kupke et al, 2001;HernandezAcosta et al, 2002), and overexpression of this enzyme leads to improved plant tolerance to salt and osmotic stress (Espinosa-Ruiz et al, 1999;Yonamine et al, 2004).…”

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An Arabidopsis Mutant Impaired in Coenzyme A Biosynthesis Is Sugar Dependent for Seedling Establishment

et al. 2006

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Once the plant coenzyme A (CoA) biosynthetic pathway has been elucidated by comparative genomics, it is feasible to analyze the physiological relevance of CoA biosynthesis in plant life. To this end, we have identified and characterized Arabidopsis (Arabidopsis thaliana) T-DNA knockout mutants of two CoA biosynthetic genes, HAL3A and HAL3B. The HAL3A gene encodes a 4#-phosphopantothenoyl-cysteine decarboxilase that generates 4#-phosphopantetheine. A second gene, HAL3B, whose gene product is 86% identical to that of HAL3A, is present in the Arabidopsis genome. HAL3A appears to have a predominant role over HAL3B according to their respective mRNA expression levels. The hal3a-1, hal3a-2, and hal3b mutants were viable and showed a similar growth rate as that in wild-type plants; in contrast, a hal3a-1 hal3b double mutant was embryo lethal. Unexpectedly, seedlings that were null for HAL3A and heterozygous for HAL3B (aaBb genotype) displayed a sucrose (Suc)-dependent phenotype for seedling establishment, which is in common with mutants defective in b-oxidation. This phenotype was genetically complemented in aaBB siblings of the progeny and chemically complemented by pantethine. In contrast, seedling establishment of Aabb plants was not Suc dependent, proving a predominant role of HAL3A over HAL3B at this stage. Total fatty acid and acyl-CoA measurements of 5-d-old aaBb seedlings in medium lacking Suc revealed stalled storage lipid catabolism and impaired CoA biosynthesis; in particular, acetyl-CoA levels were reduced by approximately 80%. Taken together, these results provide in vivo evidence for the function of HAL3A and HAL3B, and they point out the critical role of CoA biosynthesis during early postgerminative growth.

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“…In the next step, PPC is oxidatively decarboxylated to 4Ј-phosphopantothenoylaminoenethiol by the NH 2 -terminal FMNbinding CoaC domain of Dfp (6 -9). Subsequent reduction of 4Ј-phosphopantothenoylaminoenethiol to 4Ј-phosphopantetheine by the reduced cofactor FMNH 2 depends on the conserved cysteine residue of the 16-amino acid 4Ј-phosphopantothenoylcysteine binding clamp, 151 PDSGSQACGDIGPGRM (6,8,9). Binding of 4Ј-phosphopantothenoylcysteine also involves the Asn residue of the PXMNXXMW motif, which contacts the carboxyl group (8, 10).…”

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confidence: 99%

“…Subsequent reduction of 4Ј-phosphopantothenoylaminoenethiol to 4Ј-phosphopantetheine by the reduced cofactor FMNH 2 depends on the conserved cysteine residue of the 16-amino acid 4Ј-phosphopantothenoylcysteine binding clamp, 151 PDSGSQACGDIGPGRM (6,8,9). Binding of 4Ј-phosphopantothenoylcysteine also involves the Asn residue of the PXMNXXMW motif, which contacts the carboxyl group (8,10). The presence of conserved CoA biosynthetic genes indicates that all Archaea convert 4Ј-phosphopantothenate into coenzyme A by using CoaB, CoaC, CoaD, and CoaE activities, although cloning and functional characterization of archaebacterial coenzyme A biosynthetic genes has not been published until now (11).…”

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4′-Phosphopantetheine Biosynthesis in Archaea

Kupke

Schwarz²

2006

Journal of Biological Chemistry

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Coenzyme A (CoA) and 2 are essential cofactors for many enzymatic reactions, and acyl-CoA derivatives are key intermediates in energy metabolism. 4Ј-Phosphopantetheine is a cofactor of enzymes that play a role in the biosynthesis of fatty acids, polypeptide antibiotics, and polyketides. The thiol group of the cysteamine moiety of coenzyme A is the functional group because it activates substrates as thioesters.Coenzyme A is synthesized from pantothenate in five steps, and all of the genes involved in the biosynthesis of the cofactor in eubacteria, plants, and human have recently been cloned and characterized. In the first step, pantothenate is phosphorylated to 4Ј-phosphopantothenate by pantothenate kinase, which is encoded by the coaA gene. Then, (R)-4Ј-phospho-N-pantothenoylcysteine (PPC) is synthesized by the addition of cysteine to 4Ј-phosphopantothenate (CoaB activity), and in the next step, PPC is decarboxylated to 4Ј-phosphopantetheine (CoaC activity). 4Ј-Phosphopantetheine is converted to coenzyme A by the enzymes 4Ј-phosphopantetheine adenylyltransferase (CoaD) and dephospho-CoA kinase (CoaE; reviewed in Ref. 1).The key reaction in coenzyme A biosynthesis, the synthesis of the phosphopeptide-like cofactor 4Ј-phosphopantetheine from 4Ј-phosphopantothenate and cysteine, is catalyzed in Escherichia coli and in most eubacteria by the bifunctional Dfp (CoaBC) flavoprotein in a multistep process (Fig. 1) (2). 4Ј-Phosphopantothenate is activated by reaction with CTP; the 4Ј-phosphopantothenoyl-cytidylate formed is attacked by cysteine, and PPC is synthesized (2-4). Crystal structure analysis of E. coli CoaB (5) revealed the 4Ј-phosphopantothenate and CTP binding motifs of CoaB. The nucleobase binding motif II of eubacterial CTP-binding CoaBs deviates from that of eukaryotic ATP-binding PPC synthetases. In E. coli Dfp the sequence reads 307 NPDIV, whereas the sequence is 210 VPKLL in the human enzyme (residues shown in boldface are those conserved in eubacterial/eukaryotic enzymes). In the next step, PPC is oxidatively decarboxylated to 4Ј-phosphopantothenoylaminoenethiol by the NH 2 -terminal FMNbinding CoaC domain of Dfp (6 -9). Subsequent reduction of 4Ј-phosphopantothenoylaminoenethiol to 4Ј-phosphopantetheine by the reduced cofactor FMNH 2 depends on the conserved cysteine residue of the 16-amino acid 4Ј-phosphopantothenoylcysteine binding clamp, 151 PDSGSQACGDIGPGRM (6,8,9). Binding of 4Ј-phosphopantothenoylcysteine also involves the Asn residue of the PXMNXXMW motif, which contacts the carboxyl group (8, 10). The presence of conserved CoA biosynthetic genes indicates that all Archaea convert 4Ј-phosphopantothenate into coenzyme A by using CoaB, CoaC, CoaD, and CoaE activities, although cloning and functional characterization of archaebacterial coenzyme A biosynthetic genes has not been published until now (11). In this paper, we have characterized the bifunctional Dfp protein of Methanocaldococcus jannaschii. The 5Ј-coaC part and the 3Ј-coaB part of the archaebacterial dfp gene were expressed in E. coli,...

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Crystal Structure of the Plant PPC Decarboxylase AtHAL3a Complexed with an Ene-thiol Reaction Intermediate

Cited by 45 publications

References 30 publications

Functional Characterization of the Yeast Ppz1 Phosphatase Inhibitory Subunit Hal3

Functional Characterization of the Yeast Ppz1 Phosphatase Inhibitory Subunit Hal3

An Arabidopsis Mutant Impaired in Coenzyme A Biosynthesis Is Sugar Dependent for Seedling Establishment

4′-Phosphopantetheine Biosynthesis in Archaea

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