RESUMO
It is known that bacterial group II phosphopantetheinyl transferases (PPTases) usually phosphopantetheinylate acyl carrier proteins (ACPs) involved in the secondary metabolism. For example, a bacterial group II PPTase SchPPT has been known to phosphopantetheinylate only ACPs involved in secondary metabolism, such as scn ACP0-2 and scn ACP7. In this study, we found two bacterial group II PPTases, Hppt and Sppt, could phosphopantetheinylate not only scn ACP0-2 and scn ACP7, but also sch FAS ACP, an ACP involved in primary metabolism. Swapping of the N terminus and C terminus of PPTases showed that (i) both the hybrids Hppt-Sppt and Sppt-Hppt could phosphopantetheinylate sch FAS ACP but not scn ACP0-2; (ii) both the hybrids Sppt-SchPPT and SchPPT-Sppt lost abilities to phosphopantetheinylate sch FAS ACP and scn ACP0-2. Hppt and Sppt represent group II PPTases which phosphopantetheinylate both ACPs involved in primary metabolism and ACPs involved in secondary metabolism.
Assuntos
Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Metabolismo Basal , Metabolismo Secundário , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismo , Sequência de Aminoácidos , Bactérias/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Catálise , Ativação Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Dados de Sequência Molecular , Filogenia , Domínios e Motivos de Interação entre Proteínas , Transferases (Outros Grupos de Fosfato Substituídos)/química , Transferases (Outros Grupos de Fosfato Substituídos)/genéticaRESUMO
Phosphopantetheinyl transferases (PPTases) play essential roles in both primary metabolisms and secondary metabolisms via post-translational modification of acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs). In this study, an industrial FK506 producing strain Streptomyces tsukubaensis L19, together with Streptomyces avermitilis, was identified to contain the highest number (five) of discrete PPTases known among any species thus far examined. Characterization of the five PPTases in S. tsukubaensis L19 unveiled that stw ACP, an ACP in a type II PKS, was phosphopantetheinylated by three PPTases FKPPT1, FKPPT3, and FKACPS; sts FAS ACP, the ACP in fatty acid synthase (FAS), was phosphopantetheinylated by three PPTases FKPPT2, FKPPT3, and FKACPS; TcsA-ACP, an ACP involved in FK506 biosynthesis, was phosphopantetheinylated by two PPTases FKPPT3 and FKACPS; FkbP-PCP, an PCP involved in FK506 biosynthesis, was phosphopantetheinylated by all of these five PPTases FKPPT1-4 and FKACPS. Our results here indicate that the functions of these PPTases complement each other for ACPs/PCPs substrates, suggesting a complicate phosphopantetheinylation network in S. tsukubaensis L19. Engineering of these PPTases in S. tsukubaensis L19 resulted in a mutant strain that can improve FK506 production.
Assuntos
Proteínas de Bactérias/metabolismo , Redes e Vias Metabólicas , Streptomyces/enzimologia , Transferases (Outros Grupos de Fosfato Substituídos)/metabolismo , Proteína de Transporte de Acila/genética , Proteína de Transporte de Acila/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Cromatografia Líquida de Alta Pressão , Fermentação , Genoma Bacteriano/genética , Espectrometria de Massas , Família Multigênica , Mutação , Homologia de Sequência de Aminoácidos , Streptomyces/genética , Streptomyces/metabolismo , Tacrolimo/metabolismo , Transferases (Outros Grupos de Fosfato Substituídos)/genéticaRESUMO
UNLABELLED: Acyltransferase (AT) domains of polyketide synthases (PKSs) usually use coenzyme A (CoA) as an acyl donor to transfer common acyl units to acyl carrier protein (ACP) domains, initiating incorporation of acyl units into polyketides. Two clinical immunosuppressive agents, FK506 and FK520, are biosynthesized by the same PKSs in several Streptomyces strains. In this study, characterization of AT4FkbB (the AT domain of the fourth module of FK506 PKS) in transacylation reactions showed that AT4FkbB recognizes both an ACP domain (ACPT csA) and CoA as acyl donors for transfer of a unique allylmalonyl (AM) unit to an acyl acceptor ACP domain (ACP4FkbB), resulting in FK506 production. In addition, AT4FkbB uses CoA as an acyl donor to transfer an unusual ethylmalonyl (EM) unit to ACP4FkbB, resulting in FK520 production, and transfers AM units to non-native ACP acceptors. Characterization of AT4FkbB in self-acylation reactions suggests that AT4FkbB controls acyl unit specificity in transacylation reactions but not in self-acylation reactions. Generally, AT domains of PKSs only recognize one acyl donor; however, we report here that AT4FkbB recognizes two acyl donors for the transfer of different acyl units. DATABASE: Nucleotide sequence data have been submitted to the GenBank database under accession numbers KJ000382 and KJ000383.
Assuntos
Proteína de Transporte de Acila/química , Aciltransferases/química , Coenzima A/química , Policetídeo Sintases/química , Tacrolimo/metabolismo , Sequência de Bases , Cromatografia Líquida de Alta Pressão , Dados de Sequência Molecular , Família Multigênica , Estrutura Terciária de Proteína , Streptomyces/metabolismo , Especificidade por SubstratoRESUMO
Daptomycin, a novel cyclic lipopeptide antibiotic against Gram-positive bacteria, is produced by Streptomyces roseosporus. Though its biosynthetic mechanism, structural shuffling and fermentation optimization have been extensively studied, little is understood about its production regulation at the transcriptional levels. Here we reported that dptR2, encoding a DeoR-type regulator located close to the daptomycin biosynthesis gene cluster in S. roseosporus SW0702, is required for daptomycin production, but not for the expression of daptomycin gene cluster, suggesting that DptR2 was not a pathway-specific regulator. Furthermore, EMSA and qRT-PCR analysis suggested that DptR2 was positively auto-regulated by binding to its own promoter. Meanwhile, the binding sites on the dptR2 promoter were determined by a DNase I footprinting assay, and the essentiality of the inverted complementary sequences in the protected region for DptR2 binding was assessed. Our results for the first time reported the regulation of daptomycin production at the transcriptional level in S. roseosporus.
Assuntos
Proteínas de Bactérias/metabolismo , Daptomicina/biossíntese , Regulação Bacteriana da Expressão Gênica/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/metabolismo , Streptomyces/genética , Proteínas de Bactérias/genética , Sequência de Bases , Sítios de Ligação/genética , Dados de Sequência Molecular , Ligação Proteica/genética , Proteínas Repressoras/genética , Streptomyces/metabolismo , Transcrição GênicaRESUMO
In Streptomyces coelicolor, the ECF sigma factor SigT negatively regulates cell differentiation, and is degraded by ClpP protease in a dual positive feedback manner. Here we further report that the proteasome is required for degradation of SigT, but not for degradation of its anti-sigma factor RstA, and RstA can protect SigT from degradation independent of the proteasome. Meanwhile, deletion of the proteasome showed reduced production of secondary metabolites, and the fermentation medium from wild type could promote SigT degradation. Furthermore, overexpression of redD or actII-orf4 in the proteasome-deficiency mutant resulted in SigT degradation and over-production of both undecylprodigiosin and actinorhodin. Therefore the proteasome is required for SigT degradation by affecting the production of secondary metabolites during cell differentiation.
Assuntos
Proteínas de Bactérias/metabolismo , Diferenciação Celular , Complexo de Endopeptidases do Proteassoma/metabolismo , Fator sigma/metabolismo , Streptomyces coelicolor/citologia , Streptomyces coelicolor/metabolismo , Antraquinonas/metabolismo , Prodigiosina/análogos & derivados , Prodigiosina/biossíntese , ProteóliseRESUMO
Phosphopantetheinyl transferases (PPTases), which play an essential role in both primary and secondary metabolism, are magnesium binding enzymes. In this study, we characterized the magnesium binding residues of all known group II PPTases by biochemical and evolutionary analysis. Our results suggested that group II PPTases could be classified into two subgroups, two-magnesium-binding-residue-PPTases containing the triad Asp-Xxx-Glu and three-magnesium-binding-residue-PPTases containing the triad Asp-Glu-Glu. Mutations of two three-magnesium-binding-residue-PPTases and one two-magnesium-binding-residue-PPTase indicate that the first and the third residues in the triads are essential to activities; the second residues in the triads are non-essential. Although variations of the second residues in the triad Asp-Xxx-Glu exist throughout the whole phylogenetic tree, the second residues are conserved in animals, plants, algae, and most prokaryotes, respectively. Evolutionary analysis suggests that: the animal group II PPTases may originate from one common ancestor; the plant two-magnesium-binding-residue-PPTases may originate from one common ancestor; the plant three-magnesium-binding-residue-PPTases may derive from horizontal gene transfer from prokaryotes.