The diversity of modular polyketide synthase （PKS） genes in sediments of Ardley Island in Antarctica, was studied by restriction fragment length polymorphism （RFLP） analysis. Phylogenetic analysis of 14 amino acid...The diversity of modular polyketide synthase （PKS） genes in sediments of Ardley Island in Antarctica, was studied by restriction fragment length polymorphism （RFLP） analysis. Phylogenetic analysis of 14 amino acid （AA） sequences indicates that the identified ketosynthase （KS） domains were clustered with those from diverse bacterial groups, including Cyanobacteria, γ-Proteobacteria, Actinobacteria, Firmicutes, and some unidentified microorganisms from marine sponge, bryozoan and other environmental samples. The obtained KS domains showed 43%–81% similarity at the AA level to reference sequences in GenBank. Six identified KS domains showed diverse sequences of the motif （VQTACSTS） that was used to identify the hybrid PKS/nonribosomal peptide synthetase （NRPS） enzyme complex, and formed a new branch. These results reveal a high diversity and novelty of PKS genes in antarctic sediments.展开更多
Polyketides are one of the largest groups of natural products produced by bacteria, fungi, and plants. Many of these metabolites have highly complex chemical structures and very important biological activities, includ...Polyketides are one of the largest groups of natural products produced by bacteria, fungi, and plants. Many of these metabolites have highly complex chemical structures and very important biological activities, including antibiotic, anticancer, immunosuppressant, and anti-cholesterol activities. In the past two decades, extensive investigations have been carried out to understand the molecular mechanisms for polyketide biosynthesis. These efforts have led to the development of various rational approaches toward engineered biosynthesis of new polyketides. More recently, the research efforts have shifted to the elucidation of the three-dimentional structure of the complex enzyme machineries for polyketide biosynthesis and to the exploitation of new sources for polyketide production, such as filamentous fungi and marine microorganisms. This review summarizes our general understanding of the biosynthetic mechanisms and the progress in engineered biosynthesis of polyketides.展开更多
Polyketide synthases(PKSs)are megasynthases with multiple autonomously folding domains,which operate cooperatively in the PKS assemblies to synthesize specific polyketide scaffolds.Any nonreactive intermediates tether...Polyketide synthases(PKSs)are megasynthases with multiple autonomously folding domains,which operate cooperatively in the PKS assemblies to synthesize specific polyketide scaffolds.Any nonreactive intermediates tethered to acyl carrier protein(ACP)domain in the PKS will block the elongation process of polyketide chains.In this study,we systematically elucidate the editing function of fungal typeⅡthioesterases(TEIIs)to hydrolyze ACP domain-bounded nonreactive acyl groups,which are uploaded by substrate promiscuous fungal phosphopantetheinyl transferase.Thereof,the TEIIs encoded in gene clusters of nonreducing PKS with reductase domain exhibit universal editing function.Besides,editing function was also found for TEIIs encoded in gene clusters of highly-reducing PKS with condensation domain.Hence,the editing TEIIs with function of recovery PKS are applied to improve the yield of the fungal polyketides in vivo.Our study provides valuable insights into the editing process of fungal PKSs,highlights the crucial role of TEIIs in enhancing polyketide production and introduces a novel metabolic engineering strategy for fungal polyketide biosynthesis by leveraging the editing function of TEIIs.展开更多
目的 :探索恶性胸腹水上清中游离胸苷酸合成酶(TS)、β-tubulinⅢm RNA的表达,以及游离TS、β-tubulinⅢ表达和患者5-氟尿嘧啶(5-FU)、多西紫杉醇药物敏感性的关系。方法:收集43例进展期肿瘤患者的恶性胸/腹水,分离、提取游离核酸,分离...目的 :探索恶性胸腹水上清中游离胸苷酸合成酶(TS)、β-tubulinⅢm RNA的表达,以及游离TS、β-tubulinⅢ表达和患者5-氟尿嘧啶(5-FU)、多西紫杉醇药物敏感性的关系。方法:收集43例进展期肿瘤患者的恶性胸/腹水,分离、提取游离核酸,分离肿瘤细胞。实时荧光定量RT-PCR分别检测游离上清和肿瘤细胞中TS和β-tubulinⅢm RNA表达;ATP-TCA方法检测肿瘤细胞5-FU、多西紫杉醇的敏感性。结果:TS和β-tubulinⅢm RNA在恶性胸/腹水游离上清中的检出率为98%。与配对的肿瘤细胞相比,游离上清中TS m RNA表达水平高(P=0.02)。在胃肠肿瘤患者中,游离上清中TS m RNA表达水平与5-FU药物敏感性相关(P=0.002)。尽管观察到游离上清中β-tubulinⅢm RNA高表达者多西紫杉醇药物敏感性高的趋势,但差异没有统计学意义。结论:晚期肿瘤患者恶性胸腹水游离上清中可检测到游离TS、β-tubulin III m RNA的表达。在胃肠肿瘤患者中,游离上清TS m RNA表达水平与5-FU药物敏感相关。展开更多
Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases（PKS） and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based...Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases（PKS） and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based PCR assay targeting type Ⅱ polyketide synthases was performed. Among the 167 marine actinomycetes strains screened, twelve strains were identified as the ＂positive＂ strains possessing type Ⅱ PKS-encoding genes based on the sequencing of PCR products. One of the 12 ＂positive＂ strains, Streptomyces sp. PKU-MA00218 was selected for the large-scale fermentation based on the HPLC and TLC analysis. Four angucyclinones, 6-deoxy-8-O-methylrabelomycin（1）, 8-O-methylrabelomycin（2）, 8-O-methyltetrangulol（3）, C-ring cleavage product of angucyclinone C（4）, were isolated and their structures were elucidated based on spectroscopic analyses. The isolation of angucyclinones 1–4 highlights the power of genome mining technologies based on biosynthetic knowledge in natural products discovery.展开更多
Lipid and phenolic metabolism are important for pollen exine formation. In Arabidopsis, polyketide synthases （PKSs） are essential for both sporopollenin biosynthesis and exine formation. Here, we characterized the r...Lipid and phenolic metabolism are important for pollen exine formation. In Arabidopsis, polyketide synthases （PKSs） are essential for both sporopollenin biosynthesis and exine formation. Here, we characterized the role of a polyketide synthase （OsPKS2） in male reproduction of rice （Oryza sativa）. Recombinant OsPKS2 catalyzed the condensation of fatty acyl-CoA with malonyl- CoA to generate triketide and tetraketide α-pyrones, the main components of pollen exine. Indeed, the ospks2 mutant had defective exine patterning and was male sterile. However, the mutant showed no significant reduction in sporopollenin accumulation. Compared with the WT （wild type）, ospks2 displayed unconfined and amorphous tectum and nexine layers in the exine, and less organized Ubisch bodies. Like the pksb/lap5 mutant of the Arabidopsis ortholog, ospks2 showed broad alterations in the profiles of anther-related phenolic compounds. However, unlike pksb/laps, in which most detected phenolics were substantially decreased, ospks2 accumu- lated higher levels of phenolics. Based on these results and our observation that OsPKS2 is unable to fully restore the exine defects in the pksb/laps, we propose that PKS proteins have functionally diversified during evolution. Collectively, our results suggest that PKSs represent a conserved and diversified biochemical pathway for anther and pollen development in higher plants.展开更多
基金The National Natural Science Foundation of China under contract No.40406029China Ocean Mineral Resources Research & Development Association Funds under contract No.DYXM-115-02-2-04
文摘The diversity of modular polyketide synthase （PKS） genes in sediments of Ardley Island in Antarctica, was studied by restriction fragment length polymorphism （RFLP） analysis. Phylogenetic analysis of 14 amino acid （AA） sequences indicates that the identified ketosynthase （KS） domains were clustered with those from diverse bacterial groups, including Cyanobacteria, γ-Proteobacteria, Actinobacteria, Firmicutes, and some unidentified microorganisms from marine sponge, bryozoan and other environmental samples. The obtained KS domains showed 43%–81% similarity at the AA level to reference sequences in GenBank. Six identified KS domains showed diverse sequences of the motif （VQTACSTS） that was used to identify the hybrid PKS/nonribosomal peptide synthetase （NRPS） enzyme complex, and formed a new branch. These results reveal a high diversity and novelty of PKS genes in antarctic sediments.
基金Supported in part byNSF (MCB-0614916)Nebraska Research Initiatives (NRI), Redox Biology Center (RCB) Pilot Grant, andNSFC Oversea Young Scholar Award (No. 30428023)+1 种基金The research was performed in facilities renovated with support from NIH (RR015468-01)JORGENSON Joel, MARESCHAndrew, and VOGELER Chad are supported by the UCARE program at University of Nebraska-Lincoln
文摘Polyketides are one of the largest groups of natural products produced by bacteria, fungi, and plants. Many of these metabolites have highly complex chemical structures and very important biological activities, including antibiotic, anticancer, immunosuppressant, and anti-cholesterol activities. In the past two decades, extensive investigations have been carried out to understand the molecular mechanisms for polyketide biosynthesis. These efforts have led to the development of various rational approaches toward engineered biosynthesis of new polyketides. More recently, the research efforts have shifted to the elucidation of the three-dimentional structure of the complex enzyme machineries for polyketide biosynthesis and to the exploitation of new sources for polyketide production, such as filamentous fungi and marine microorganisms. This review summarizes our general understanding of the biosynthetic mechanisms and the progress in engineered biosynthesis of polyketides.
基金supported financially by the National Natural Science Foundation of China(Nos.82225042,T2192973)the CAMS Innovation Fund for Medical Sciences(No.CIFMS 2021-I2M1-029)。
文摘Polyketide synthases(PKSs)are megasynthases with multiple autonomously folding domains,which operate cooperatively in the PKS assemblies to synthesize specific polyketide scaffolds.Any nonreactive intermediates tethered to acyl carrier protein(ACP)domain in the PKS will block the elongation process of polyketide chains.In this study,we systematically elucidate the editing function of fungal typeⅡthioesterases(TEIIs)to hydrolyze ACP domain-bounded nonreactive acyl groups,which are uploaded by substrate promiscuous fungal phosphopantetheinyl transferase.Thereof,the TEIIs encoded in gene clusters of nonreducing PKS with reductase domain exhibit universal editing function.Besides,editing function was also found for TEIIs encoded in gene clusters of highly-reducing PKS with condensation domain.Hence,the editing TEIIs with function of recovery PKS are applied to improve the yield of the fungal polyketides in vivo.Our study provides valuable insights into the editing process of fungal PKSs,highlights the crucial role of TEIIs in enhancing polyketide production and introduces a novel metabolic engineering strategy for fungal polyketide biosynthesis by leveraging the editing function of TEIIs.
文摘目的 :探索恶性胸腹水上清中游离胸苷酸合成酶(TS)、β-tubulinⅢm RNA的表达,以及游离TS、β-tubulinⅢ表达和患者5-氟尿嘧啶(5-FU)、多西紫杉醇药物敏感性的关系。方法:收集43例进展期肿瘤患者的恶性胸/腹水,分离、提取游离核酸,分离肿瘤细胞。实时荧光定量RT-PCR分别检测游离上清和肿瘤细胞中TS和β-tubulinⅢm RNA表达;ATP-TCA方法检测肿瘤细胞5-FU、多西紫杉醇的敏感性。结果:TS和β-tubulinⅢm RNA在恶性胸/腹水游离上清中的检出率为98%。与配对的肿瘤细胞相比,游离上清中TS m RNA表达水平高(P=0.02)。在胃肠肿瘤患者中,游离上清中TS m RNA表达水平与5-FU药物敏感性相关(P=0.002)。尽管观察到游离上清中β-tubulinⅢm RNA高表达者多西紫杉醇药物敏感性高的趋势,但差异没有统计学意义。结论:晚期肿瘤患者恶性胸腹水游离上清中可检测到游离TS、β-tubulin III m RNA的表达。在胃肠肿瘤患者中,游离上清TS m RNA表达水平与5-FU药物敏感相关。
基金National Natural Science Foundation of China(Grant No.81573326)
文摘Angucyclinones are aromatic polyketides produced by type Ⅱ polyketide synthases（PKS） and are mainly found in terrestrial actinomycetes. To discover more angucyclinones from marine actinomycetes, a genomic DNA-based PCR assay targeting type Ⅱ polyketide synthases was performed. Among the 167 marine actinomycetes strains screened, twelve strains were identified as the ＂positive＂ strains possessing type Ⅱ PKS-encoding genes based on the sequencing of PCR products. One of the 12 ＂positive＂ strains, Streptomyces sp. PKU-MA00218 was selected for the large-scale fermentation based on the HPLC and TLC analysis. Four angucyclinones, 6-deoxy-8-O-methylrabelomycin（1）, 8-O-methylrabelomycin（2）, 8-O-methyltetrangulol（3）, C-ring cleavage product of angucyclinone C（4）, were isolated and their structures were elucidated based on spectroscopic analyses. The isolation of angucyclinones 1–4 highlights the power of genome mining technologies based on biosynthetic knowledge in natural products discovery.
基金supported by funds from the National Key Research and Development Program of China(No.2016YFD0101107)the National Key Basic Research Developments Program of the Ministry of Science and Technology of China(No.2013CB126902)+1 种基金the National Natural Science Foundation of China(No.31322040,31670309)the Innovative Research Team of the Ministry of Education and the 111 Project(No.B14016)
文摘Lipid and phenolic metabolism are important for pollen exine formation. In Arabidopsis, polyketide synthases （PKSs） are essential for both sporopollenin biosynthesis and exine formation. Here, we characterized the role of a polyketide synthase （OsPKS2） in male reproduction of rice （Oryza sativa）. Recombinant OsPKS2 catalyzed the condensation of fatty acyl-CoA with malonyl- CoA to generate triketide and tetraketide α-pyrones, the main components of pollen exine. Indeed, the ospks2 mutant had defective exine patterning and was male sterile. However, the mutant showed no significant reduction in sporopollenin accumulation. Compared with the WT （wild type）, ospks2 displayed unconfined and amorphous tectum and nexine layers in the exine, and less organized Ubisch bodies. Like the pksb/lap5 mutant of the Arabidopsis ortholog, ospks2 showed broad alterations in the profiles of anther-related phenolic compounds. However, unlike pksb/laps, in which most detected phenolics were substantially decreased, ospks2 accumu- lated higher levels of phenolics. Based on these results and our observation that OsPKS2 is unable to fully restore the exine defects in the pksb/laps, we propose that PKS proteins have functionally diversified during evolution. Collectively, our results suggest that PKSs represent a conserved and diversified biochemical pathway for anther and pollen development in higher plants.
