Lithocarpus litseifolius is rich in the chalcones phloridzin and trilobatin, the biosynthesis pathways of which have not been fully demonstrated. Chalcone synthase(CHS) is the first key rate-limiting enzyme in the biosynthesis of flavonoids in plants. To explore the functions of CHS gene family in chalcone synthesis of L. litseifolius, this study screened out two CHS genes(LlCHS1 and LlCHS2) from the transcriptome data of this plant, and then bioinformatics analysis and functional characterization were performed for the two genes. The bioinformatics analysis showed that LlCHS1 and LlCHS2 were acidic hydrophilic stable proteins with no transmembrane domain, composed of 395 and 390 amino acid residues, respectively. Both of them contained the characteristic amino acid sequence "WGVLFGFGPGL" and highly conserved active sites(Cys-164, Phe-215, His-303, and Asn-336) of the CHS family. The phylogenetic tree showed that LlCHS1 shared the same clade with similar genes in Aquilaria sinensis, and LlCHS2 was closely related to similar genes in Malus domestica. Under exogenous addition of phloretic acid, co-expression of LlCHS1 or LlCHS2 with Aa4CL from Aromatoleum aromaticum in Escherichia coli catalyzed the production of phloretin from phloretic acid. This study laid a theoretical foundation for revealing the functions of CHS in plants and provided new enzymatic modules for producing phloretin by synthetic biology.
Acyltransferases/chemistry* ; Phylogeny ; Plant Proteins/chemistry* ; Cloning, Molecular ; Amino Acid Sequence

Polygonum cuspidatum polyketide synthase 1 (PcPKS1) has the catalytic activity of chalcone synthase (CHS) and benzylidene acetone synthase (BAS), which can catalyze the production of polyketides naringenin chalcone and benzylidene acetone, and then catalyze the synthesis of flavonoids or benzylidene acetone. In this study, three amino acid sites (Thr133, Ser134, Ser33) that may affect the function of PcPKS1 were identified by analyzing the sequences of PcPKS1, the BAS from Rheum palmatum and the CHS from Arabidopsis thaliana, as well as the conformation of the catalytic site of the enzyme. Molecular modification of PcPKS1 was carried out by site-directed mutagenesis, and two mutants were successfully obtained. The in vitro enzymatic reactions were carried out, and the differences in activity were detected by high performance liquid chromatography (HPLC). Finally, mutants T133LS134A and S339V with bifunctional activity were obtained. In addition to bifunctional activities of BAS and CHS, the modified PcPKS1 had much higher BAS activity than that of the wild type PcPKS1 under the conditions of pH 7.0 and pH 9.0, respectively. It provides a theoretical basis for future use of PcPKS1 in genetic engineering to regulate the biosynthesis of flavonoids and raspberry ketones.
Amino Acid Sequence ; Fallopia japonica/metabolism* ; Polyketide Synthases/chemistry* ; Acetone ; Mutagenesis, Site-Directed ; Flavonoids/metabolism* ; Acyltransferases/metabolism*

Perilla (Perilla frutescens L.) is an important edible-medicinal oil crop, with its seed containing 46%-58% oil. Of perilla seed oil, α-linolenic acid (C18:3) accounts for more than 60%. Lysophosphatidic acid acyltransferase (LPAT) is one of the key enzymes responsible for triacylglycerol assembly in plant seeds, controlling the metabolic flow from lysophosphatidic acid to phosphatidic acid. In this study, the LPAT2 gene from the developing seeds of perilla was cloned and designated as PfLPAT2. The expression profile of PfLPAT2 gene was examined in various tissues and different seed development stages of perilla (10, 20, 30, and 40 days after flowering, DAF) by quantitative real-time PCR (qRT-PCR). In order to detect the subcellular localization of PfLPAT2 protein, a fusion expression vector containing PfLPAT2 and GFP was constructed and transformed into Nicotiana benthamiana leaves by Agrobacterium-mediated infiltration. In order to explore the enzymatic activity and biological function of PfLPAT2 protein, an E. coli expression vector, a yeast expression vector and a constitutive plant overexpression vector were constructed and transformed into an E. coli mutant SM2-1, a wild-type Saccharomyces cerevisiae strain INVSc1, and a common tobacco (Nicotiana tabacum, variety: Sumsun NN, SNN), respectively. The results showed that the PfLPAT2 open reading frame (ORF) sequence was 1 155 bp in length, encoding 384 amino acid residues. Functional structure domain prediction showed that PfLPAT2 protein has a typical conserved domain of lysophosphatidic acid acyltransferase. qRT-PCR analysis indicated that PfLPAT2 gene was expressed in all tissues tested, with the peak level in seed of 20 DAF of perilla. Subcellular localization prediction showed that PfLPAT2 protein is localized in cytoplasm. Functional complementation assay of PfLPAT2 in E. coli LPAAT mutant (SM2-1) showed that PfLPAT2 could restore the lipid biosynthesis of SM2-1 cell membrane and possess LPAT enzyme activity. The total oil content in the PfLPAT2 transgenic yeast was significantly increased, and the content of each fatty acid component changed compared with that of the non-transgenic control strain. Particularly, oleic acid (C18:1) in the transgenic yeast significantly increased, indicating that PfLPAT2 has a higher substrate preference for C18:1. Importantly, total fatty acid content in the transgenic tobacco leaves increased by about 0.42 times compared to that of the controls, with the C18:1 content doubled. The increased total oil content and the altered fatty acid composition in transgenic tobacco lines demonstrated that the heterologous expression of PfLPAT2 could promote host oil biosynthesis and the accumulation of health-promoting fatty acids (C18:1 and C18:3). This study will provide a theoretical basis and genetic elements for in-depth analysis of the molecular regulation mechanism of perilla oil, especially the synthesis of unsaturated fatty acids, which is beneficial to the genetic improvement of oil quality of oil crops.
Acyltransferases ; Cloning, Molecular ; Escherichia coli/metabolism* ; Fatty Acids ; Perilla frutescens/metabolism* ; Plant Oils ; Plant Proteins/metabolism* ; Saccharomyces cerevisiae/metabolism* ; Seeds/chemistry* ; Tobacco/genetics*

Chalcone synthase( CHS) and chalcone isomerase( CHI) are key enzymes in the biosynthesis pathway of flavonoids. In this study,unigenes for CHS and CHI were screened from the transcriptome database of Arisaema heterophyllum. The open reading frame( ORFs) of chalcone synthase( Ah CHS) and chalcone isomerase( Ah CHI) were cloned from the plant by RT-PCR. The physicochemical properties,expression and structure characteristics of the encoded proteins Ah CHS and Ah CHI were analyzed. The ORFs of Ah CHS and Ah CHI were 1 176,630 bp in length and encoded 392,209 amino acids,respectively. Ah CHS functioned as a symmetric homodimer. The N-terminal helix of one monomer entwined with the corresponding helix of another monomer. Each CHS monomer consisted of two structural domains. In particular,four conserved residues define the active site. The tertiary structure of Ah CHI revealed a novel open-faced β-sandwich fold. A large β-sheet( β4-β11) and a layer of α-helices( α1-α7) comprised the core structure. The residues spanning β4,β5,α4,and α6 in the three-dimensional structure were conserved among CHIs from different species. Notably,these structural elements formed the active site on the protein surface,and the topology of the active-site cleft defined the stereochemistry of the cyclization reaction. The homology comparison showed that Ah CHS had the highest similarity to the CHS of Anthurium andraeanum,while Ah CHI had the highest similarity to the CHI of Paeonia delavayi. This study provided the basis for the functional study of Ah CHS and Ah CHI and the further study on plant flavonoid biosynthesis pathway.
Acyltransferases ; chemistry ; genetics ; Arisaema ; enzymology ; genetics ; Cloning, Molecular ; Intramolecular Lyases ; chemistry ; genetics ; Plant Proteins ; chemistry ; genetics

Based on the transcriptome data, we cloned the open reading frame of IiHCT gene from Isatis indigotica, and then performed bioinformatic analysis of the sequence. Further, we detected expression pattern in specific organs and hairy roots treated methyl jasmonate( MeJA) by RT-PCR. The IiHCT gene contains a 1 290 bp open reading frame( ORF) encoding a polypeptide of 430 amino acids. The predicted isoelectric point( pI) was 5.7, a calculated molecular weight was about 47.68 kDa. IiHCT was mainly expressed in stem and undetectable in young root, leaf and flower bud. After the treatment of MeJA, the relative expression level of IiHCT increased rapidly. The expression level of IiHCT was the highest at 4 h and maintained two fold to control during 24 h. In this study, cloning of IiHCT laid the foundation for illustrating the biosynthesis mechanism of phenylpropanoids in I. indigotica.
Acyltransferases ; chemistry ; genetics ; metabolism ; Amino Acid Sequence ; Cloning, Molecular ; Gene Expression Regulation, Plant ; Isatis ; chemistry ; classification ; enzymology ; genetics ; Models, Molecular ; Molecular Sequence Data ; Open Reading Frames ; Phylogeny ; Plant Proteins ; chemistry ; genetics ; metabolism ; Quinic Acid ; metabolism ; Sequence Alignment ; Shikimic Acid ; metabolism

OBJECTIVEThe study aimed to clone the open reading frame of chalcone synthase (CHS) from Aquilaria sinensis and analyze the bioinformatics and expression of the gene.

METHODOne unique sequence containing CHS domain was discovered in our previous reported wound transcriptome dataset of A. sinensis. The open reading frame of CHS was cloned by RT-PCR strategy with the template of mixed RNA extracted from A. sinensis stem which treated by different wound time. The bioinformatic analysis of this gene and its corresponding protein was performed. The AsCHS1 expression in calli was analyzed with histone gene as an internal control gene under wound condition by qRT-PCR technique.

RESULTOne unique sequence of CHS, named as AsCHS1, was cloned from A. sinensis. The full length of AsCHS1 cDNA was containing a 1 192 bp ORF that encoded 397 amino acids. The result of qRT-PCR displayed that the highest expression level was at 12 h, which indicated that it was possibly involved in early-stage response to wound.

CONCLUSIONCloning and analyzing AsCHS1 gene from A. sinensis provided basic information for study the function and expression regulation of AsCHS1 in the flavonoids biosynthesis.

Acyltransferases ; genetics ; Base Sequence ; Cloning, Molecular ; Computational Biology ; DNA, Complementary ; chemistry ; genetics ; DNA, Plant ; chemistry ; genetics ; Drugs, Chinese Herbal ; Flavonoids ; metabolism ; Gene Expression Regulation, Enzymologic ; Gene Expression Regulation, Plant ; Models, Molecular ; Molecular Sequence Data ; Phylogeny ; Plant Proteins ; genetics ; Plant Stems ; chemistry ; enzymology ; genetics ; Plants, Medicinal ; Protein Structure, Tertiary ; RNA, Messenger ; genetics ; RNA, Plant ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA ; Thymelaeaceae ; chemistry ; enzymology ; genetics

Plant type III polyketide synthase (PKS) generates backbones of a variety of plant secondary metabolites with diverse functions, and has long been models to elucidate the relationship between the three-dimensional structure and function. More than 80 type IIII PKS crystal structures with different functions have been reported in Protein Data Bank, including the crystal structures of the well-studied Chalcone Synthase of plant type III PKS, as well as the 6 other kinds of PKSs in the family, which are critical for understanding the structural basis for diverse starter molecule selectivity, polyketide chain length and the cyclization reaction. Structure-based analysis and site-directed mutagenesis are foundation for the investigation of enzyme engineering, genetic and metabolic engineering. This review summarized 7 plant-specific type III PKS in the aspects of their crystal structures and functions.
Acyltransferases ; chemistry ; genetics ; physiology ; Amino Acid Sequence ; Catalysis ; Chalcones ; Crystallization ; Flavanones ; Genetic Engineering ; Metabolic Engineering ; Molecular Sequence Data ; Plant Proteins ; chemistry ; genetics ; physiology ; Plants ; enzymology ; genetics ; Protein Structure, Secondary ; Substrate Specificity

To clarify the important functional residues in the active site of N-myristoyltransferase (NMT), a novel antifungal drug target, and to guide the design of specific inhibitors, multiple sequence alignments were performed on the NMT family and thus evolutionary trace was constructed. The important functional residues in myristoyl CoA binding site, catalytic center and inhibitor binding site of NMT family were identified by ET analysis. The trace residues were mapped onto the active site of CaNMT. Trpl26, Asn175 and Thr211 are highly conserved trace residues and do not interact with current NMT inhibitors, which are potential novel drug binding sites for the novel inhibitor design. Pro338, Leu350, Ile352 and Ala353 are class-specific trace residues, which are important for the optimization of current NMT inhibitors. The trace residues identified by ET analysis are of great importance to study the structure-function relationship and also to guide the design of specific inhibitors.
Acyl Coenzyme A ; metabolism ; Acyltransferases ; chemistry ; genetics ; metabolism ; Amino Acid Sequence ; Animals ; Binding Sites ; Conserved Sequence ; Enzyme Inhibitors ; chemistry ; pharmacology ; Evolution, Molecular ; Humans ; Imidazoles ; chemistry ; pharmacology ; Models, Molecular ; Molecular Sequence Data ; Oligopeptides ; chemistry ; pharmacology ; Phylogeny ; Protein Structure, Tertiary ; Sequence Homology, Amino Acid

Acyltransferases ; antagonists & inhibitors ; chemistry ; Animals ; Antifungal Agents ; chemical synthesis ; pharmacology ; Benzofurans ; chemical synthesis ; pharmacology ; Benzothiazoles ; chemical synthesis ; pharmacology ; Drug Design ; Enzyme Inhibitors ; chemical synthesis ; pharmacology ; Fungi ; drug effects ; enzymology ; Imidazoles ; chemical synthesis ; pharmacology ; Molecular Structure

Polythioesters newly emerged as a type of novel polymer and they have showed great potential for application in industries. In this study, genes of butyrate kinase (buk) and phosphotransbutyrylase (ptb) from Clostridium acetobutylicum, and poly (3-hydroxybutyrate) (PHB) synthase gene from Thiocapsa pfennigii were used for construction of a metabolic pathway to synthesize the polythioesters. When 3-mercaptopropionate and 3-hydroxybutyrate were fed, poly (3-mercaptopropoinate) [poly (3MP)] and poly(3-mercaptopropionate-co-3-hydroxybutyrate) [poly(3MP-co-3HB)] were synthesized by recombinant Escherichia coli JM109 (pBPP1) harboring the constructed metabolic pathway. Results indicated clearly that all these genes are necessary for the synthesis of poly(3MP) and poly(3MP-co-3HB).
3-Hydroxybutyric Acid ; chemistry ; 3-Mercaptopropionic Acid ; chemistry ; Acyltransferases ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Gas Chromatography-Mass Spectrometry ; Models, Biological ; Molecular Weight ; Phosphate Acetyltransferase ; genetics ; metabolism ; Phosphotransferases (Carboxyl Group Acceptor) ; genetics ; metabolism ; Plasmids ; Polymers ; chemistry ; metabolism ; Spectrophotometry, Infrared