Search results for "recte"

Functional significance of membrane associated proteolysis in the toxicity of Bacillus thuringiensis Cry3Aa toxin against Colorado potato beetle.

2012

Abstract Bacillus thuringiensis Cry toxins are widely used as biocontrol agents in bioinsecticides and transgenic plants. In the three domain-Cry toxins, domain II has been identified as an important determinant of their highly specific activity against insects. In this work, we assessed the role in membrane associated proteolysis and toxicity in Colorado potato beetle (CPB) of a previously reported ADAM recognition motif present in Cry3Aa toxin domain II. We used site-directed mutagenesis to modify the Bacillus thuringiensis cry3A gene in amino acid residues 344, 346, 347, 351 and 353 of the ADAM recognition motif in Cry3Aa toxin. Cry3Aa toxin mutants displayed decreased toxicity when comp…

Extracellular loop 2 of G protein-coupled olfactory receptors is critical for odorant recognition

2021

International audience; G protein-coupled olfactory receptors (ORs) enable us to detect innumerous odorants. They are also ectopically expressed in non-olfactory tissues and emerging as attractive drug targets. ORs can be promiscuous or highly specific, which is part of a larger mechanism for odor discrimination. Here, we demonstrate that the OR extracellular loop 2 (ECL2) plays critical roles in OR promiscuity and specificity. Using site-directed mutagenesis and molecular modeling, we constructed 3D OR models in which ECL2 forms a lid over the orthosteric pocket. We demonstrate using molecular dynamics simulations that ECL2 controls the shape and the volume of the odorant-binding pocket, m…

Two amino acid residues determine the low substrate affinity of human cationic amino acid transporter-2A.

2003

Mammalian cationic amino acid transporters (CAT) differ in their substrate affinity and sensitivity to trans-stimulation. The apparent Km values for cationic amino acids and the sensitivity to trans-stimulation of CAT-1, -2B, and -3 are characteristic of system y+. In contrast, CAT-2A exhibits a 10-fold lower substrate affinity and is largely independent of substrate at the trans-side of the membrane. CAT-2A and -2B demonstrate such divergent transport properties, even though their amino acid sequences differ only in a stretch of 42 amino acids. Here, we identify two amino acid residues within this 42-amino acid domain of the human CAT-2A protein that are responsible for the apparent low af…

Identification of Single Amino Acid Residues of Human IL-6 Involved in Receptor Binding and Signal Initiation

1996

The pleiotropic cytokine interleukin-6 (IL-6) has been predicted to be a protein with four antiparallel alpha-helices. On target cells, IL-6 interacts with a specific ligand binding receptor subunit (IL-6R), and this complex associates with the signal-transducing subunit gp130. Human IL-6 acts on human and murine cells, whereas murine IL-6 is only active on murine cells. The construction of chimeric human/murine IL-6 proteins has allowed us to define a region (residues 77-95, region 2c) within the human IL-6 protein that is important for IL-6R binding and a region (residues 50-55, region 2a2) that is important for IL-6R dependent gp130 interaction. Guided by sequence alignment and molecular…

Quark Contraction Tool -- QCT

2016

We present a Mathematica package for the calculation of Wick contractions in quantum field theories - QCT. Furthermore the package aims at automatically generating code for the calculation of physical matrix elements, suitable for numerical evaluation in a C++ program. To that end commonly used algebraic manipulations for the calculation of matrix elements in lattice QCD are implemented.

The contribution of epistasis to the architecture of fitness in an RNA virus

2004

4 pages, 2 figures.-- PMID: 15492220 [PubMed].-- PMCID: PMC524436.-- Additional information (Suppl. table S1: Relevant information about each single- and double-nucleotide substitution mutant created) available at: http://www.pnas.org/content/101/43/15376/suppl/DC1

Arabinose nucleoside triphosphates are no inhibitors for DNA-dependent RNA polymerases.

1976

1-Beta-D-arabinofuranosylcytosine-5' -triphosphate and 9-beta-D-arabinofuranosyladenosine-5' -triphosphate were found to have no inhibitory potency for both mammalian DNA-dependent RNA polymerase II and E. coli DNA-dependent RNA polymerase.

6-mercaptopurine and 9-(2-phosphonyl-methoxyethyl) adenine (PMEA) transport altered by two missense mutations in the drug transporter gene ABCC4

2008

Multiple drug resistance protein 4 (MRP4, ABCC4) belongs to the C subfamily of the ATP-binding cassette (ABC) transporter superfamily and participates in the transport of diverse antiviral and chemotherapeutic agents such as 6-mercaptopurine (6-MP) and 9-(2-phosphonyl methoxyethyl) adenine (PMEA). We have undertaken a comprehensive functional characterization of protein variants of MRP4 found in Caucasians and other ethnicities. A total of 11 MRP4 missense genetic variants (nonsynonymous SNPs), fused to green fluorescent protein (GFP), were examined in Xenopus laevis oocytes for their effect on expression, localization, and function of the transporter. Radiolabeled 6-MP and PMEA were chosen…

Production of biologically active light chain of tetanus toxin inEscherichia coli

1993

AbstractThe activity of the light (L) chain of tetanus toxin, and of mutants constructed by site-directed mutagenesis, was studied by expression and purification of the proteins from E. coli. Wild-type recombinant L chain (pTet87) was active in the inhibition of exocytosis from cultured bovine adrenal chromaffin cells, although at a level 5–15% of that of L chain purified from tetanus toxin. L chain mutants which terminated at Leu-438 (pTet89), or which contained a Cys-to-Ser mutation at residue 439 (pTet88) were equally as active as the full-length recombinant protein. The reduced activity of pTet87 L chain correlated with C-terminal proteolysis of the protein upon purification. A tryptic …

Innovative systems based on optical nanoantennas for energy harvesting application

The purpose of this study is to outline the main guidelines for the design of arrays of optical rectennas aiming to harvest energy and for the optimization of the power transfer to an external load. In particular, the novelty of this study consists in introducing the concept of the integrated design between the array of optical rectennas and the harvesting circuit able to exploit the available energy. The design of the array represents the crucial point in order to optimize the power transfer between the antenna and the load and can influence the rectenna design. On the other hand, the maximum power transfer to the load has to be obtained under matching conditions between the array and the …