53-59-8Relevant articles and documents
Schlenk
, p. 668 (1937)
Biochemical and structural basis of triclosan resistance in a novel enoyl-acyl carrier protein reductase
Khan, Raees,Zeb, Amir,Roy, Nazish,Magar, Roniya Thapa,Kim, Hyo Jeong,Lee, Keun Woo,Lee, Seon-Woo
, (2018)
Enoyl-acyl carrier protein reductases (ENR), such as FabI, FabL, FabK, and FabV, catalyze the last reduction step in bacterial type II fatty acid biosynthesis. Previously, we reported metagenome-derived ENR homologs resistant to triclosan (TCL) and highly similar to 7- hydroxysteroid dehydrogenase (7-AHSDH). These homologs are commonly found in Epsilonproteobacteria, a class that contains several human-pathogenic bacteria, including the genera Helicobacter and Campylobacter. Here we report the biochemical and predicted structural basis of TCL resistance in a novel 7-AHSDH-like ENR. The purified protein exhibited NADPH-dependent ENR activity but no 7-AHSDH activity, despite its high homology with 7-AHSDH (69% to 96%). Because this ENR was similar to FabL (41%), we propose that this metagenome-derived ENR be referred to as FabL2. Homology modeling, molecular docking, and molecular dynamic simulation analyses revealed the presence of an extrapolated six-amino-acid loop specific to FabL2 ENR, which prevented the entry of TCL into the active site of FabL2 and was likely responsible for TCL resistance. Elimination of this extrapolated loop via site-directed mutagenesis resulted in the complete loss of TCL resistance but not enzyme activity. Phylogenetic analysis suggested that FabL, FabL2, and 7-AHSDH diverged from a common short-chain dehydrogenase reductase family. This study is the first to report the role of the extrapolated loop of FabL2-type ENRs in conferring TCL resistance. Thus, the FabL2 ENR represents a new drug target specific for pathogenic Epsilonproteobacteria.
Pd (core)-Au (shell) nanoparticles catalyzed conversion of NADH to NAD+ by UV-vis spectroscopy-A kinetic analysis
Gopalan,Ragupathy,Kim,Manesh,Lee
, p. 678 - 684 (2009)
Kinetics of Pd (core)-Au (shell) nanoparticles (NPs) catalyzed transformation of dihydronicotinamide adenine dinucleotide (NADH) to NAD+ was monitored by UV-vis spectroscopy. Pd (core)-Au (shell) NPs were prepared by microwave irradiation method. High resolution transmission electron microscopy image reveals the core-shell morphology. X-ray diffraction pattern shows the presence of distinct crystalline domains for Pd and Au. The changes in absorbances at 340 nm were followed for various time intervals. Rates of conversion of NADH to NAD+ were determined for different conditions. The conversion of NADH to NAD+ was to be first order with respect to NADH at lower concentrations (upto 0.04 mM) and pseudo-first-order beyond 0.04 mM. Rate constants for the Pd (core) Au-(shell) NPs catalyzed transformation of NADH to NAD+ were deduced.
Purification and kinetics of bovine kidney cortex glutathione reductase
Tandogan, Berivan,Nuray Ulusu
, p. 667 - 674 (2010)
Glutathione reductase was purified 34806-fold with a final yield of 85% from the bovine kidney cortex. Some molecular and kinetic properties of purified enzyme are investigated. Product inhibition studies showed that the enzyme obeys 'branched' mechanism: KmNADPH 18 ± 3 μM and KmGSSG 65 ± 5 μM were determined.
Purification and Characterization of NfrA1, a Bacillus subtilis Nitro/flavin Reductase Capable of Interacting with the Bacterial Luciferase
Zenno, Shuhei,Kobori, Toshiro,Tanokura, Masaru,Saigo, Kaoru
, p. 1978 - 1987 (1998)
ipa-43d is a hypothetical gene identified by the Bacillus subtilis genome project (Mol. Microbiol. 10, 371-384 1993; Nature 390, 249-256 1997). The ipa-43d protein overexpressed in E. coli was purified to homogeneity and its properties were analyzed biochemically. The ipa-43d protein was found to be tightly associated with FMN and to be capable of reducing both nitrofurazone and FMN effectively. Although the ipa-43d protein catalysis obeys the ping-pong Bi-Bi mechanism, catalysis mode was changed to the sequential mechanism upon coupling with the bioluminescent reaction. Database search showed that B. subtilis possessed four genes (ipa-44d, ytmO, yddN, and yvbT), encoding proteins similar in amino acid sequence to LuxA and LuxB of Photobacterium fischeri, and, in particular, ipa-44d is immediately adjacent to the ipa-43d gene on the chromosome.
Molecular cloning and heterologous expression of progesterone 5β-reductase from Digitalis lanata Ehrh.
Herl, Vanessa,Fischer, Gabriele,Müller-Uri, Frieder,Kreis, Wolfgang
, p. 225 - 231 (2008/02/09)
A full-length cDNA clone that encodes progesterone 5β-reductase (5β-POR) was isolated from Digitalis lanata leaves. The reading frame of the 5β-POR gene is 1170 nucleotides corresponding to 389 amino acids. For expression, a Sph1/Sal1 5β-POR fragment was cloned into the pQE vector and was transformed into Escherichia coli strain M15[pREP4]. The recombinant gene was functionally expressed and the recombinant enzyme was characterized. The Km and vmax values for the putative natural substrate progesterone were calculated to be 0.120 mM and 45 nkat mg-1 protein, respectively. Only 5β-pregnane-3,20-dione but not its α-isomer was formed when progesterone was used as the substrate. Kinetic constants for cortisol, cortexone, 4-androstene-3,17-dione and NADPH were also determined. The molecular organization of the 5β-POR gene in D. lanata was determined by Southern blot analysis. The 5β-POR is highly conserved within the genus Digitalis and the respective genes and proteins share considerable homology to putative progesterone reductases from other plant species.
