Search results for "affinity"
showing 10 items of 313 documents
Porifera Lectins: diversity, physiological roles and biotechnological potential
2015
An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell intera…
Pheromone-binding proteins of scarab beetles.
1998
: We have characterized Pheromone binding proteins (PBPs) present in the antennae of several species of scarab beetles. In most cases there was only one class of PBP, which was expressed in both sexes. Both Anomala osakana and Popillia japonica possess a single PBP, highly homologous to each other. In each species the same PBP seems to recognize both enantiomers of japonilure, which have opposite biological functions, i.e., the sex Pheromone and the behavioral antagonist (stop signal). The purified PBP of A. osakana binds both enantiomers apparently with the same low affinity. Unexpectedly, these ligands were bound by moth PBPs, which utilize Pheromones with unrelated structures. These find…
Purification by affinity chromatography of H1 RNA-Binding Proteins from rat brain
2003
Post-transcriptional regulation of mRNA metabolism is involved in processes as different as cell fate specification in development and cell response to a large variety of environmental cues. Regulation of all steps of RNA metabolism depends on RNA-binding proteins (RBPs). By using a T1 RNase protection assay, we previously identified three H1° RNA-binding factors (p40, p70 and p110), highly expressed in the rat brain. Here we report enrichment of these factors from brain extracts, obtained by affinity chromatography of biotinylated H1° RNA-protein complexes on streptavidin-conjugated paramagnetic particles. The purified proteins maintain RNA-binding ability and preference for histone messag…
Insecticidal activity of Vip3Aa, Vip3Ad, Vip3Ae, and Vip3Af from Bacillus thuringiensis against lepidopteran corn pests.
2012
Vip3Aa, Vip3Ad, Vip3Ae, and Vip3Af proteins from Bacillus thuringiensis were tested for their toxicity against Spodoptera frugiperda and Agrotis ipsilon. Vip3Ad was non-toxic to the two species. Vip3Ae and Vip3Af were significantly more toxic than Vip3Aa against S. frugiperda, both as protoxins and as toxins. Against A. ipsilon, Vip3Ae protoxin was more toxic than Vip3Aa and Vip3Af protoxins. Purification by metal-chelate affinity chromatography significantly affected Vip3Ae toxicity against the two insect species.
The Influence of Oxygen Affinity of Blood and Cerebral Blood Flow on Cerebral Oxygen Supply
1969
The quantity of oxygen transported, per unit of time, by the blood to the brain, is determined by the blood flow, the oxygen capacity, and the oxygen affinity of the blood. The O2-exchange between the blood and the tissue cells depends mainly on the oxygen transport characteristics of the blood and the O2 diffusion conditions in the blood and tissue.
Relationship between Electron Affinity and Half-Wave Reduction Potential: A Theoretical Study on Cyclic Electron-Acceptor Compounds.
2016
A high-level ab initio protocol to compute accurate electron affinities and half-wave reduction potentials is presented and applied for a series of electron-acceptor compounds with potential interest in organic electronics and redox flow batteries. The comprehensive comparison between the theoretical and experimental electron affinities not only proves the reliability of the theoretical G3(MP2) approach employed but also calls into question certain experimental measurements, which need to be revised. By using the thermodynamic cycle for the one-electron attachment reaction A+e- →A- , theoretical estimates for the first half-wave reduction potential have been computed along the series of ele…
Cruciform Electron Acceptors Based on Tetraindeno-Fused Spirofluorene
2017
Two cruciform tetraindenospirofluorene-based acceptors embedding carbonyl (Spiro-4O) and dicyanovinylene (Spiro-8CN) functionalities are synthesized in high yields. Single-crystal X-ray analysis reveals a one-dimensional π–π stacking arrangement for Spiro-4O, while Spiro-8CN adopts a unique two-dimensional isotropic π-interaction. Cyclic voltammetry suggests a high electron affinity of −3.76 eV for Spiro-8CN. Such a packing motif and low LUMO energy for Spiro-8CN are important for bulk electron transport.
Covalent modificaition of juvenile hormone binding proteins by photoaffinity labeling: An unexpected gel shift effect
1994
The 32 kD juvenile hormone binding protein (JHBP) and two 80 kD proteins in larval Manduca sexta hemolymph were labeled with [3H]FDK, a photoaffinity analog of methyl farnesoate (MF). The labeling could be completely displaced by a 30-fold excess of either MF or JH II, demonstrating that [3H]FDK binds specifically to the JH binding sites of the 32 kD JHBP and the 80 kD proteins. In addition, a high molecular-mass protein was labeled with [3H]FDK; labeling could be displaced by excess MF but not by JH II, demonstrating the selectivity in binding MF. The 32 kD JHBP also appeared to weakly bind the potent juvenoid, methoprene, at the JH binding site. Covalent modification by [3H]FDK induced a …
3'-Arylazido-beta-alanyl-2-azido ATP, a cross-linking photoaffinity label for F1ATPases.
1989
Abstract The synthesis of the 3′-arylazido-2-azido ATP derivative 3′-O-{3-[N-(4-azido-2-nitrophenyl)-amino]propionyl}2-azido-adenosine 5′-triphosphate (2,3′-DiN3ATP) is described. The bifunc tional photoreactive ATP analog is characterized spectroscopically. Photoaffinity labeling of F, ATPase from Micrococcus luteus by this analog results in the inactivation of the enzyme and in the formation of higher molecular weight cross-links,
Characterization of the DNA-binding activity of the E1 and E2 proteins and the E1/E2 complex of human papillomavirus type 33.
1997
The E1 and E2 proteins of papillomaviruses are essential for the initiation of viral DNA replication. We have purified the E2 protein of human papillomavirus type 33 (HPV-33) by immunoaffinity chromatography. The purified E2 protein bound with high affinity to all four consensus binding sites of HPV-33 (Kd approximately equal to 2 x 10(-10)M). A putative E2 binding site differing at one position in the second stem of the palindrome was not bound by E2. The E1 protein of HPV-33 purified by affinity chromatography using glutathione S-transferase as tag displayed specific DNA-binding activity in footprint analyses protecting HPV-33 nucleotides 7896 to 7909/1 to 18 from DNasel digestion. Hypers…