Offloading Role of a Discrete Thioesterase in Type II Polyketide Biosynthesis

ABSTRACT Type II polyketides are a group of secondary metabolites with various biological activities. In nature, biosynthesis of type II polyketides involves multiple enzymatic steps whereby key enzymes, including ketoacyl-synthase (KSα), chain length factor (KSβ), and acyl carrier protein (ACP), are utilized to elongate the polyketide chain through a repetitive condensation reaction. During each condensation, the biosynthesis intermediates are covalently attached to KSα or ACP via a thioester bond and are then cleaved to release an elongated polyketide chain for successive postmodification. Despite its critical role in type II polyketide biosynthesis, the enzyme and its corresponding mechanism for type II polyketide chain release through thioester bond breakage have yet to be determined. Here, kinamycin was used as a model compound to investigate the chain release step of type II polyketide biosynthesis. Using a genetic knockout strategy, we confirmed that AlpS is required for the complete biosynthesis of kinamycins. Further in vitro biochemical assays revealed high hydrolytic activity of AlpS toward a thioester bond in an aromatic polyketide-ACP analog, suggesting its distinct role in offloading the polyketide chain from ACP during the kinamycin biosynthesis. Finally, we successfully utilized AlpS to enhance the heterologous production of dehydrorabelomycin in Escherichia coli by nearly 25-fold, which resulted in 0.50 g/liter dehydrorabelomycin in a simple batch-mode shake flask culture. Taken together, our results provide critical knowledge to gain an insightful understanding of the chain-releasing process during type II polyketide synthesis, which, in turn, lays a solid foundation for future new applications in type II polyketide bioproduction.

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Stat-mediated Signaling Induced by Type I and Type II Interferons (IFNs) Is Differentially Controlled through Lipid Microdomain Association and Clathrin-dependent Endocytosis of IFN Receptors

Molecular Biology of the Cell ◽

10.1091/mbc.e06-01-0076 ◽

2006 ◽

Vol 17 (7) ◽

pp. 2896-2909 ◽

Cited By ~ 74

Author(s):

Marta Marchetti ◽

Marie-Noelle Monier ◽

Alexandre Fradagrada ◽

Keith Mitchell ◽

Florence Baychelier ◽

...

Keyword(s):

Plasma Membrane ◽

Biological Activities ◽

Critical Role ◽

Membrane Lipid ◽

Endocytic Pathway ◽

Type I ◽

Type Ii ◽

Biological Responses ◽

Signal Specificity ◽

Ifn Γ

Type I (α/β) and type II (γ) interferons (IFNs) bind to distinct receptors, although they activate the same signal transducer and activator of transcription, Stat1, raising the question of how signal specificity is maintained. Here, we have characterized the sorting of IFN receptors (IFN-Rs) at the plasma membrane and the role it plays in IFN-dependent signaling and biological activities. We show that both IFN-α and IFN-γ receptors are internalized by a classical clathrin- and dynamin-dependent endocytic pathway. Although inhibition of clathrin-dependent endocytosis blocked the uptake of IFN-α and IFN-γ receptors, this inhibition only affected IFN-α–induced Stat1 and Stat2 signaling. Furthermore, the antiviral and antiproliferative activities induced by IFN-α but not IFN-γ were also affected. Finally, we show that, unlike IFN-α receptors, activated IFN-γ receptors rapidly become enriched in plasma membrane lipid microdomains. We conclude that IFN-R compartmentalization at the plasma membrane, through clathrin-dependent endocytosis and lipid-based microdomains, plays a critical role in the signaling and biological responses induced by IFNs and contributes to establishing specificity within the Jak/Stat signaling pathway.

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New insights into bacterial type II polyketide biosynthesis

F1000Research ◽

10.12688/f1000research.10466.1 ◽

2017 ◽

Vol 6 ◽

pp. 172 ◽

Cited By ~ 26

Author(s):

Zhuan Zhang ◽

Hai-Xue Pan ◽

Gong-Li Tang

Keyword(s):

Biological Activities ◽

Genome Mining ◽

Large Family ◽

Combinatorial Biosynthesis ◽

Type Ii ◽

Polyketide Biosynthesis ◽

Aromatic Polyketides ◽

Starting Point ◽

Biosynthetic Engineering ◽

Bacterial Type

Bacterial aromatic polyketides, exemplified by anthracyclines, angucyclines, tetracyclines, and pentangular polyphenols, are a large family of natural products with diverse structures and biological activities and are usually biosynthesized by type II polyketide synthases (PKSs). Since the starting point of biosynthesis and combinatorial biosynthesis in 1984–1985, there has been a continuous effort to investigate the biosynthetic logic of aromatic polyketides owing to the urgent need of developing promising therapeutic candidates from these compounds. Recently, significant advances in the structural and mechanistic identification of enzymes involved in aromatic polyketide biosynthesis have been made on the basis of novel genetic, biochemical, and chemical technologies. This review highlights the progress in bacterial type II PKSs in the past three years (2013–2016). Moreover, novel compounds discovered or created by genome mining and biosynthetic engineering are also included.

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Design of Arylsulfonylhydrazones as Potential FabH Inhibitors: Synthesis, Antimicrobial Evaluation and Molecular Docking

Medicinal Chemistry ◽

10.2174/1573406415666191122111228 ◽

2019 ◽

Vol 15 ◽

Author(s):

Thais Batista Fernandes ◽

Natanael Dante Segretti ◽

Felipe Rebello Lourenço ◽

Thalita Marcílio Cândido ◽

André Rolim Baby ◽

...

Keyword(s):

Antioxidant Activity ◽

Molecular Docking ◽

Antimicrobial Agents ◽

Acyl Carrier Protein ◽

Condensation Reaction ◽

Lung Fibroblast ◽

Fibroblast Cells ◽

Human Lung Fibroblast ◽

Persistent Problem ◽

E Coli

Background: Antimicrobial resistance is a persistent problem about infections treatment and carries needing for develop new antimicrobial agents. Inhibiting of bacterial β-ketoacyl acyl carrier protein synthase III (FabH), which catalyzes the condensation reaction between a CoA-attached acetyl group and an ACP-attached malonyl group in bacteria is an interesting strategy to find new antibacterial agents. Objective: The aim of this work was to design and synthesize arylsulfonylhydrazones potentially FabH inhibitors and evaluate their antimicrobial activity. Methods: MIC50 of sulfonylhydrazones against E. coli and S. aureus was determined. Antioxidant activity was evaluated by DPPH (1-1’-diphenyl-2-picrylhydrazyl) assay and cytotoxicity against LL24 lung fibroblast cells was verified by MTT method. Principal component analysis (PCA) was performed in order to suggest a structure-activity relationship. Molecular docking allowed to propose sulfonylhydrazones interactions with FabH. Results: The most active compound showed activity against S. aureus and E. coli, with MIC50 = 0.21 and 0.44 µM, respectively. PCA studies correlated better activity to lipophilicity and molecular docking indicated that sulfonylhydrazone moiety is important to hydrogen-bond with FabH while methylcatechol ring performs π-π stacking interaction. The DPPH assay revealed that some sulfonylhydrazones derived from the methylcatechol series had antioxidant activity. None of the evaluated compounds was cytotoxic to human lung fibroblast cells, suggesting that the compounds might be considered safe at the tested concentration. Conclusion: Arylsufonylhydrazones is a promising scaffold to be explored for design of new antimicrobial agents.

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Chalcones: As potent α-amylase enzyme inhibitors; synthesis, in vitro, and in silico studies

Medicinal Chemistry ◽

10.2174/1573406416666200611103039 ◽

2020 ◽

Vol 16 ◽

Author(s):

Mahboob Ali ◽

Momin Khan ◽

Khair Zaman ◽

Abdul Wadood ◽

Maryam Iqbal ◽

...

Keyword(s):

In Silico ◽

Enzyme Inhibitors ◽

Biological Activities ◽

Condensation Reaction ◽

Type Ii Diabetes Mellitus ◽

Spectroscopic Techniques ◽

Chalcone Derivatives ◽

In Silico Studies ◽

Wide Range

: Background: The inhibition of α-amylase enzyme is one of the best therapeutic approach for the management of type II diabetes mellitus. Chalcone possesses a wide range of biological activities. Objective: In the current study chalcone derivatives (1-17) were synthesized and evaluated their inhibitory potential against α-amylase enzyme. Method: For that purpose, a library of substituted (E)-1-(naphthalene-2-yl)-3-phenylprop-2-en-1-ones was synthesized by ClaisenSchmidt condensation reaction of 2-acetonaphthanone and substituted aryl benzaldehyde in the presence of base and characterized via different spectroscopic techniques such as EI-MS, HREI-MS, 1H-, and 13C-NMR. Results: Sixteen synthetic chalcones were evaluated for in vitro porcine pancreatic α-amylase inhibition. All the chalcones demonstrated good inhibitory activities in the range of IC50 = 1.25 ± 1.05 to 2.40 ± 0.09 μM as compared to the standard commercial drug acarbose (IC50 = 1.34 ± 0.3 μM). Conclusion: Chalcone derivatives (1-17) were synthesized, characterized, and evaluated for their α-amylase inhibition. SAR revealed that electron donating groups in the phenyl ring have more influence on enzyme inhibition. However, to insight the participation of different substituents in the chalcones on the binding interactions with the α-amylase enzyme, in silico (computer simulation) molecular modeling analyses were carried out.

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DFT Study and Synthesis of Novel Bioactive Bispyrazole Using Mg/AlLDH as a Solid Base Catalyst

Current Chemical Biology ◽

10.2174/2212796814999200918175018 ◽

2020 ◽

Vol 14 ◽

Author(s):

Soufiane Akhramez ◽

Youness Achour ◽

Mustapha Diba ◽

Lahoucine Bahsis ◽

Hajiba Ouchetto ◽

...

Keyword(s):

Dft Calculations ◽

Experimental Finding ◽

Biological Activities ◽

Condensation Reaction ◽

Aromatic Aldehydes ◽

Mechanistic Study ◽

Knoevenagel Reaction ◽

Solid Base ◽

Reaction Conditions ◽

Aryl Aldehyde

Background: In this study, an efficient synthesis of novel bispyrazole heterocyclic molecules by condensation of substituted aromatic aldehydes with 1,3-diketo-N-phenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst is reported. The attractive features of this protocol are as follows: mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Methods: The bispyrazole derivatives 3a-m were prepared by condensation reaction of substituted aromatic aldehydes with 1,3-diketo-Nphenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst under THF solvent at the refluxing temperature. Objective: To synthesize a novel bispyrazole heterocyclic molecule may be have important biological activities and thus can be good candidates for pharmaceutical applications. Results: This protocol describes the Synthesis of Bioactive Compounds under mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Conclusion: In summary, the pharmacologically interesting bis-pyrazole derivatives have been synthesized through Mg/Al-LDH as a solid base catalyst, in THF as solvent. Thus, the synthesized bioactive compounds containing the pyrazole ring may be have important biological activities and thus can be good candidates for pharmaceutical applications. Therefore, the catalyst Mg/Al-LDH showed high catalytic activity. Besides, a series of bispyrazole molecules were synthesized with a good yield and easy separation of the catalyst by simple filtration. Moreover, DFT calculations and reactivity indexes are used to explain the selectivity of the condensation reaction between aryl benzaldehyde and 1,3-diketo-Nphenylpyrazole via Knoevenagel reaction, and the results are in good agreement with the experimental finding.

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Phenotypic Analysis of Mice Lacking the Tmprss2-Encoded Protease

Molecular and Cellular Biology ◽

10.1128/mcb.26.3.965-975.2006 ◽

2006 ◽

Vol 26 (3) ◽

pp. 965-975 ◽

Cited By ~ 105

Author(s):

Tom S. Kim ◽

Cynthia Heinlein ◽

Robert C. Hackman ◽

Peter S. Nelson

Keyword(s):

Serine Protease ◽

Serine Proteases ◽

Biological Activities ◽

Type Ii ◽

Phenotypic Analysis ◽

Normal Prostate ◽

Prostate Hyperplasia ◽

Transmembrane Serine Protease

ABSTRACT Tmprss2 encodes an androgen-regulated type II transmembrane serine protease (TTSP) expressed highly in normal prostate epithelium and has been implicated in prostate carcinogenesis. Although in vitro studies suggest protease-activated receptor 2 may be a substrate for TMPRSS2, the in vivo biological activities of TMPRSS2 remain unknown. We generated Tmprss2 −/− mice by disrupting the serine protease domain through homologous recombination. Compared to wild-type littermates, Tmprss2 −/− mice developed normally, survived to adulthood with no differences in protein levels of prostatic secretions, and exhibited no discernible abnormalities in organ histology or function. Loss of TMPRSS2 serine protease activity did not influence fertility, reduce survival, result in prostate hyperplasia or carcinoma, or alter prostatic luminal epithelial cell regrowth following castration and androgen replacement. Lack of an observable phenotype in Tmprss2 −/− mice was not due to transcriptional compensation by closely related Tmprss2 homologs. We conclude that the lack of a discernible phenotype in Tmprss2 −/− mice suggests functional redundancy involving one or more of the type II transmembrane serine protease family members or other serine proteases. Alternatively, TMPRSS2 may contribute a specialized but nonvital function that is apparent only in the context of stress, disease, or other systemic perturbation.

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Identification of active site residues implies a two-step catalytic mechanism for acyl-ACP thioesterase

Biochemical Journal ◽

10.1042/bcj20180470 ◽

2018 ◽

Vol 475 (23) ◽

pp. 3861-3873 ◽

Cited By ~ 3

Author(s):

Fuyuan Jing ◽

Marna D. Yandeau-Nelson ◽

Basil J. Nikolau

Keyword(s):

Fatty Acid ◽

Sequence Alignment ◽

Fatty Acid Synthase ◽

Catalytic Mechanism ◽

Fatty Acid Biosynthesis ◽

Tertiary Structure ◽

Acyl Carrier Protein ◽

Cocos Nucifera ◽

Catalytic Residue ◽

Thioester Bond

In plants and bacteria that use a Type II fatty acid synthase, isozymes of acyl-acyl carrier protein (ACP) thioesterase (TE) hydrolyze the thioester bond of acyl-ACPs, terminating the process of fatty acid biosynthesis. These TEs are therefore critical in determining the fatty acid profiles produced by these organisms. Past characterizations of a limited number of plant-sourced acyl-ACP TEs have suggested a thiol-based, papain-like catalytic mechanism, involving a triad of Cys, His, and Asn residues. In the present study, the sequence alignment of 1019 plant and bacterial acyl-ACP TEs revealed that the previously proposed Cys catalytic residue is not universally conserved and therefore may not be a catalytic residue. Systematic mutagenesis of this residue to either Ser or Ala in three plant acyl-ACP TEs, CvFatB1 and CvFatB2 from Cuphea viscosissima and CnFatB2 from Cocos nucifera, resulted in enzymatically active variants, demonstrating that this Cys residue (Cys348 in CvFatB2) is not catalytic. In contrast, the multiple sequence alignment, together with the structure modeling of CvFatB2, suggests that the highly conserved Asp309 and Glu347, in addition to previously proposed Asn311 and His313, may be involved in catalysis. The substantial loss of catalytic competence associated with site-directed mutants at these positions confirmed the involvement of these residues in catalysis. By comparing the structures of acyl-ACP TE and the Pseudomonas 4-hydroxybenzoyl-CoA TE, both of which fold in the same hotdog tertiary structure and catalyze the hydrolysis reaction of thioester bond, we have proposed a two-step catalytic mechanism for acyl-ACP TE that involves an enzyme-bound anhydride intermediate.

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Sticky swinging arm dynamics: studies of an acyl carrier protein domain from the mycolactone polyketide synthase

Biochemical Journal ◽

10.1042/bcj20160041 ◽

2016 ◽

Vol 473 (8) ◽

pp. 1097-1110 ◽

Cited By ~ 14

Author(s):

Steven Vance ◽

Olga Tkachenko ◽

Ben Thomas ◽

Mona Bassuni ◽

Hui Hong ◽

...

Keyword(s):

Polyketide Synthase ◽

Acyl Carrier Protein ◽

Protein Domain ◽

Carrier Protein ◽

Protein Surface ◽

Prosthetic Group ◽

Polyketide Biosynthesis ◽

Covalently Linked

When covalently linked to an acyl carrier protein (ACP) and loaded with acyl substrate-mimics, some 4′-phosphopantetheine prosthetic group arms swing freely, whereas others stick to the protein surface, suggesting a possible mode of interaction with enzyme domains during polyketide biosynthesis.

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