scholarly journals Mutational analysis of the triclosan-binding region of enoyl-ACP (acyl-carrier protein) reductase from Plasmodium falciparum

2004 ◽  
Vol 381 (3) ◽  
pp. 735-741 ◽  
Author(s):  
Mili KAPOOR ◽  
Jayashree GOPALAKRISHNAPAI ◽  
Namita SUROLIA ◽  
Avadhesha SUROLIA
Keyword(s):  
Plasmodium Falciparum ◽  
Binding Affinity ◽  
Mutational Analysis ◽  
Acyl Carrier Protein ◽  
Striking Difference ◽  
Carrier Protein ◽  
Type I ◽  
Type Ii ◽  
Wild Type ◽  
Binding Region

Triclosan, a known antibacterial, acts by inhibiting enoyl-ACP (acyl-carrier protein) reductase (ENR), a key enzyme of the type II fatty acid synthesis (FAS) system. Plasmodium falciparum, the human malaria-causing parasite, harbours the type II FAS; in contrast, its human host utilizes type I FAS. Due to this striking difference, ENR has emerged as an important target for the development of new antimalarials. Modelling studies, and the crystal structure of P. falciparum ENR, have highlighted the features of ternary complex formation between the enzyme, triclosan and NAD+ [Suguna, A. Surolia and N. Surolia (2001) Biochem. Biophys. Res. Commun. 283, 224–228; Perozzo, Kuo, Sidhu, Valiyaveettil, Bittman, Jacobs, Fidock, and Sacchettini (2002) J. Biol. Chem. 277, 13106–13114; and Swarnamukhi, Kapoor, N. Surolia, A. Surolia and Suguna (2003) PDB1UH5]. To address the issue of the importance of the residues involved in strong specific and stoichiometric binding of triclosan to P. falciparum ENR, we mutated the following residues: Ala-217, Asn-218, Met-281, and Phe-368. The affinity of all the mutants was reduced for triclosan as compared with the wild-type enzyme to different extents. The most significant mutation was A217V, which led to a greater than 7000-fold decrease in the binding affinity for triclosan as compared with wild-type PfENR. A217G showed only 10-fold reduction in the binding affinity. Thus, these studies point out significant differences in the triclosan-binding region of the P. falciparum enzyme from those of its bacterial counterparts.

scholarly journals Slow-tight-binding inhibition of enoyl-acyl carrier protein reductase from Plasmodium falciparum by triclosan

2004 ◽  
Vol 381 (3) ◽  
pp. 719-724 ◽  
Author(s):  
Mili KAPOOR ◽  
C. Chandramouli REDDY ◽  
M. V. KRISHNASASTRY ◽  
Namita SUROLIA ◽  
Avadhesha SUROLIA
Keyword(s):  
Plasmodium Falciparum ◽  
Fatty Acid ◽  
Rate Constants ◽  
Enzyme Inhibitor ◽  
Acyl Carrier Protein ◽  
Tight Binding ◽  
Carrier Protein ◽  
Type I ◽  
Type Ii ◽  
Inhibitor Complex

Triclosan is a potent inhibitor of FabI (enoyl-ACP reductase, where ACP stands for acyl carrier protein), which catalyses the last step in a sequence of four reactions that is repeated many times with each elongation step in the type II fatty acid biosynthesis pathway. The malarial parasite Plasmodium falciparum also harbours the genes and is capable of synthesizing fatty acids by utilizing the enzymes of type II FAS (fatty acid synthase). The basic differences in the enzymes of type I FAS, present in humans, and type II FAS, present in Plasmodium, make the enzymes of this pathway a good target for antimalarials. The steady-state kinetics revealed time-dependent inhibition of FabI by triclosan, demonstrating that triclosan is a slow-tight-binding inhibitor of FabI. The inhibition followed a rapid equilibrium step to form a reversible enzyme–inhibitor complex (EI) that isomerizes to a second enzyme–inhibitor complex (EI*), which dissociates at a very slow rate. The rate constants for the isomerization of EI to EI* and the dissociation of EI* were 5.49×10−2 and 1×10−4 s−1 respectively. The Ki value for the formation of the EI complex was 53 nM and the overall inhibition constant Ki* was 96 pM. The results match well with the rate constants derived independently from fluorescence analysis of the interaction of FabI and triclosan, as well as those obtained by surface plasmon resonance studies [Kapoor, Mukhi, N. Surolia, Sugunda and A. Surolia (2004) Biochem. J. 381, 725–733].

Two Different UGT1A1 Mutations causing Crigler–Najjar Syndrome types I and II in an Iranian Family

2015 ◽  
Vol 24 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Yoshihiro Maruo ◽  
Mahdiyeh Behnam ◽  
Shinichi Ikushiro ◽  
Sayuri Nakahara ◽  
Narges Nouri ◽  
...  
Keyword(s):  
Serum Bilirubin ◽  
Total Serum Bilirubin ◽  
Total Serum ◽  
Compound Heterozygous ◽  
Type I ◽  
Syndrome Type ◽  
Type Ii ◽  
Wild Type ◽  
Iranian Family ◽  
Udp Glucuronosyltransferase

Background: Crigler–Najjar syndrome type I (CN-1) and type II (CN-2) are rare hereditary unconjugated hyperbilirubinemia disorders. However, there have been no reports regarding the co-existence of CN-1 and CN-2 in one family. We experienced a case of an Iranian family that included members with either CN-1 or CN-2. Genetic analysis revealed a mutation in the bilirubin UDP-glucuronosyltransferase (UGT1A1) gene that resulted in residual enzymatic activity.Case report: The female proband developed severe hyperbilirubinemia [total serum bilirubin concentration (TB) = 34.8 mg/dL] with bilirubin encephalopathy (kernicterus) and died after liver transplantation. Her family history included a cousin with kernicterus (TB = 30.0 mg/dL) diagnosed as CN-1. Her great grandfather (TB unknown) and uncle (TB = 23.0 mg/dL) developed jaundice, but without any treatment, they remained healthy as CN-2. Results: The affected cousin was homozygous for a novel frameshift mutation (c.381insGG, p.C127WfsX23). The affected uncle was compound heterozygous for p.C127WfsX23 and p.V225G linked with A(TA)7TAA. p.V225G-UGT1A1 reduced glucuronidation activity to 60% of wild-type. Thus, linkage of A(TA)7TAA and p.V225G might reduce UGT1A1 activity to 18%–36 % of the wild-type. Conclusion: Genetic and in vitro expression analyses are useful for accurate genetic counseling for a family with a history of both CN-1 and CN-2. Abbreviations: CN-1: Crigler–Najjar syndrome type I; CN-2: Crigler–Najjar syndrome type II; GS: Gilbert syndrome; UGT1A1: bilirubin UDP-glucuronosyltransferase; WT: Wild type; TB: total serum bilirubin.

Role of common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of murine mast cells

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2172-2180 ◽  
Author(s):  
Kotaro Suzuki ◽  
Hiroshi Nakajima ◽  
Norihiko Watanabe ◽  
Shin-ichiro Kagami ◽  
Akira Suto ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Cytokine Receptor ◽  
Type I ◽  
Dependent Manner ◽  
Type Ii ◽  
Wild Type ◽  
Peritoneal Mast Cells ◽  
The Common

Abstract The regulatory roles of the common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of mast cells were determined using γc-deficient (γc−) and Jak3-deficient (Jak3−) mice. Although the mast cells in γc− and Jak3− mice were morphologically indistinguishable from those in wild-type mice, the number of peritoneal mast cells was decreased in γc− and Jak3− mice as compared with that in wild-type mice. Among γc-related cytokines, interleukin (IL)-4 and IL-9, but not IL-2, IL-7, or IL-15, enhanced the proliferation and survival of bone marrow–derived mast cells (BMMCs) from wild-type mice. However, the effects of IL-4 and IL-9 were absent in BMMCs from γc− and Jak3−mice. In addition, IL-4Rα, γc, and Jak3, but not IL-2Rβ or IL-7Rα, were expressed in BMMCs. In contrast, IL-13 did not significantly induce the proliferation and survival of BMMCs even from wild-type mice, and IL-13Rα1 was not expressed in BMMCs. Furthermore, IL-4 phosphorylated the 65-kd isoform of Stat6 in BMMCs from wild-type mice but not from γc− and Jak3− mice. These results indicate that γc- and Jak3-dependent signaling is essential for IL-4– and IL-9–induced proliferation and survival of murine mast cells, that the effects of IL-4 are mediated by type I IL-4R and that type II IL-4R is absent on mast cells, and that IL-4 phosphorylates the 65-kd isoform of Stat6 in mast cells in a γc- and Jak3-dependent manner.

scholarly journals Modular type I polyketide synthase acyl carrier protein domains share a common N-terminally extended fold

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luisa Moretto ◽  
Rachel Heylen ◽  
Natalie Holroyd ◽  
Steven Vance ◽  
R. William Broadhurst
Keyword(s):  
Polyketide Synthase ◽  
Acyl Carrier Protein ◽  
Protein Domains ◽  
Carrier Protein ◽  
Type I

scholarly journals Comparison of CRISPR and Marker-Based Methods for the Engineering of Phage T7

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 193 ◽  
Author(s):  
Aurelija M. Grigonyte ◽  
Christian Harrison ◽  
Paul R. MacDonald ◽  
Ariadna Montero-Blay ◽  
Matthew Tridgett ◽  
...  
Keyword(s):  
Therapeutic Agents ◽  
Bacteriophage T7 ◽  
Type I ◽  
Type Ii ◽  
Selection Mechanism ◽  
Wild Type ◽  
Phage T7 ◽  
Fundamental Biology ◽  
Type Phage ◽  
Host Genes

With the recent rise in interest in using lytic bacteriophages as therapeutic agents, there is an urgent requirement to understand their fundamental biology to enable the engineering of their genomes. Current methods of phage engineering rely on homologous recombination, followed by a system of selection to identify recombinant phages. For bacteriophage T7, the host genes cmk or trxA have been used as a selection mechanism along with both type I and II CRISPR systems to select against wild-type phage and enrich for the desired mutant. Here, we systematically compare all three systems; we show that the use of marker-based selection is the most efficient method and we use this to generate multiple T7 tail fibre mutants. Furthermore, we found the type II CRISPR-Cas system is easier to use and generally more efficient than a type I system in the engineering of phage T7. These results provide a foundation for the future, more efficient engineering of bacteriophage T7.

scholarly journals A Light‐Activated Acyl Carrier Protein “Trap” for Intermediate Capture in Type II Iterative Polyketide Biocatalysis

2019 ◽  
Vol 25 (72) ◽  
pp. 16515-16518
Author(s):  
Samantha L. Kilgour ◽  
David P. A. Kilgour ◽  
Panward Prasongpholchai ◽  
Peter B. O'Connor ◽  
Manuela Tosin
Keyword(s):  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
Type Ii

scholarly journals IN-SILICO SCREENING AGAINST ANTIMALARIAL TARGET PLASMODIUM FALCIPARUM ENOYL-ACYL CARRIER PROTEIN REDUCTASE

2017 ◽  
Vol 10 (17) ◽  
pp. 127
Author(s):  
Berwi Fazri Pamudi ◽  
Azizahwati Azizahwati ◽  
Arry Yanuar
Keyword(s):  
Plasmodium Falciparum ◽  
Virtual Screening ◽  
In Silico ◽  
Acyl Carrier Protein ◽  
Parasitic Infection ◽  
Antimalarial Drugs ◽  
Chemotherapeutic Agents ◽  
Effective Vaccine ◽  
Carrier Protein ◽  
In Silico Screening

  Objective: Malaria is a parasitic infection that causes worldwide health problems. The absence of an effective vaccine and Plasmodium strains that are resistant to antimalarial drugs emphasize the importance of developing new chemotherapeutic agents. The use of computers for in-silico screening, or virtual screening, is currently being developed as a method for discovering antimalarial drugs. One of the enzymes that can support the development of the malaria parasite is the Plasmodium falciparum enoyl-acyl carrier protein reductase (PfENR). Inhibition of these enzymes leads to Type II lipid biosynthesis inhibition on the parasite.Methods: This research investigates the use of virtual screening to find PfENR inhibitor candidates. A molecular docking method using GOLD software and the medicinal plants in Indonesia database will be used. This target has been optimized by the removal of residues and the addition of charge. Ligand is expected to be an inhibitor of PfENR.Results: In-silico screening, or virtual screening, found that the top five compounds with the highest GOLD score at trial are kaempferol 3-rhamnosyl- (1-3)-rhamnosyl-(1-6)-glucoside; cyanidin 3,5-di-(6-malonylglucoside); 8-hydroxyapigenin 8-(2’’, 4’’-disulfato glucuronide); epigallocatechin 3,5,-di- O-gallat; quercetin 3,4’-dimethyl ether 7-alpha-L-arabinofuranosyl-(1-6)-glucoside. They had GOLD scores of 94.73, 95.90, 86.46, 85.39, and 84.40, respectively.Conclusions: There are two candidate inhibitor compounds from tea (Camellia sinensis), which have potential for development as an antimalarial drug, which are kaempferol 3-rhamnosyl-(1-3)-rhamnosyl-(1-6)-glucoside and epigallocatechin 3,5,-di-O-gallate, with a GOLD score of 94.73 and 85.39, respectively.

Solution Structure of an Acyl Carrier Protein Domain from a Fungal Type I Polyketide Synthase,

Biochemistry ◽  
2010 ◽  
Vol 49 (10) ◽  
pp. 2186-2193 ◽  
Author(s):  
Pakorn Wattana-amorn ◽  
Christopher Williams ◽  
Eliza Płoskoń ◽  
Russell J. Cox ◽  
Thomas J. Simpson ◽  
...  
Keyword(s):  
Solution Structure ◽  
Polyketide Synthase ◽  
Acyl Carrier Protein ◽  
Protein Domain ◽  
Carrier Protein ◽  
Type I

scholarly journals Phosphatidylinositol-4,5 Bisphosphate Produced by PIP5KIγ Regulates Gelsolin, Actin Assembly, and Adhesion Strength of N-Cadherin Junctions

2007 ◽  
Vol 18 (8) ◽  
pp. 3026-3038 ◽  
Author(s):  
T. Y. El Sayegh ◽  
P. D. Arora ◽  
K. Ling ◽  
C. Laschinger ◽  
P. A. Janmey ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Intercellular Adhesion ◽  
Actin Binding ◽  
Type I ◽  
Actin Assembly ◽  
Wild Type ◽  
Binding Region ◽  
A Cell ◽  
Intercellular Adhesions ◽  
Phosphatidylinositol 4

Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin–mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or transfection with GFP-PH-PLCδ showed that PI(4,5)P2 was enriched at sites of N-cadherin adhesions and this enrichment required activated Rac1. Isoform-specific immunostaining for type I phosphatidylinositol 4-phosphate 5 kinase (PIP5KI) showed that PIP5KIγ was spatially associated with N-cadherin–Fc beads. Association of PIP5KIγ with N-cadherin adhesions was in part dependent on the activation of RhoA. Transfection with catalytically inactive PIP5KIγ blocked the enrichment of PI(4,5)P2 around beads. Catalytically inactive PIP5KIγ or a cell-permeant peptide that mimics and competes for the PI(4,5)P2-binding region of the actin-binding protein gelsolin inhibited incorporation of actin monomers in response to N-cadherin ligation and reduced intercellular adhesion strength by more than twofold. Gelsolin null fibroblasts transfected with a gelsolin severing mutant containing an intact PI(4,5)P2 binding region, demonstrated intercellular adhesion strength similar to wild-type transfected controls. We conclude that PIP5KIγ-mediated generation of PI(4,5)P2 at sites of N-cadherin contacts regulates intercellular adhesion strength, an effect due in part to PI(4,5)P2-mediated regulation of gelsolin.

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