Search results for "binding"

Drug Binding Properties of Tyrosine-Modified Human Serum Albumin

1978

Human serum albumin (HSA) has only a small number of specific binding sites for drugs. There are facts indicating that tyrosine residues may be involved in these binding sites. Thus we modified HSA with tetranitromethan, a reagent specific for tyrosine residues in proteins. As derived from an UV-absorption quotient three albumins with a degree of modification of two, five and eight residues per molecule were obtained. Only for the albumin with eight residues modified a small reduction of ordered secondary structure was found.

The binding of G-protein to rod outer segment phospholipids at the nitrogen–water interface

1989

In the visual process, one photoexcited rhodopsin (R*) catalyzes the activation of hundreds of G-proteins. It remains to be determined whether G-protein and R* find one another by membrane surface diffusion of these components (diffusion model) or by diffusion of G-protein through the aqueous phase (hopping model). A monolayer of each main rod outer segment (ROS) phospholipid interacting with a subphase containing G-protein, has been used to simulate the interaction of G-protein with the cytoplasmic surface of discal membranes. The possible diffusion of G-protein through the aqueous phase was then measured by observing its adsorption–desorption in the monolayer of each main ROS phospholipi…

Local vs global motions in protein folding

2013

It is of interest to know whether local fluctuations in a polypeptide chain play any role in the mechanism by which the chain folds to the native structure of a protein. This question is addressed by analyzing folding and non-folding trajectories of a protein; as an example, the analysis is applied to the 37-residue triple β-strand WW domain from the Formin binding protein 28 (FBP28) (PDB ID: 1E0L). Molecular dynamics (MD) trajectories were generated with the coarse-grained united-residue force field, and one- and two-dimensional free-energy landscapes (FELs) along the backbone virtual-bond angle θ and backbone virtual-bond-dihedral angle γ of each residue, and principal components, respect…

Dysfunction of Torr causes a Harlequin-type ichthyosis-like phenotype in Drosophila melanogaster

2019

AbstractPrevention of desiccation is a constant challenge for terrestrial organisms. Land insects have an extracellular coat, the cuticle, that plays a major role in protection against exaggerated water loss. Here, we report that the ABC transporter Torr - a human ABCA12 paralog - contributes to the waterproof barrier function of the cuticle in the fruit fly Drosophila melanogaster. We show that the reduction or elimination of Torr function provokes rapid desiccation. Torr is also involved in defining the inward barrier against xenobiotics penetration. Consistently, the amounts of cuticular hydrocarbons that are involved in cuticle impermeability decrease markedly when Torr activity is redu…

Azide and chloride binding to carboxypeptidase A in the presence of L-phenylalanine

1990

The interaction of chloride with native and cobalt (Co)-substituted carboxypeptidase-A (CPD) has been investigated by 35Cl nuclear magnetic resonance (NMR) spectroscopy in the presence and absence of L-Phe. The affinity constants of azide and chloride toward the Co(II)CPD·L-Phe complex have been measured by electronic spectroscopy. The correlation times determining T1 and T2 for the 35Cl nuclei are related to movements inside the cavity. In the presence of L-Phe, the anions bind to the metal with a relatively high affinity at pH values below 6. Anion binding to the Co enzyme can be analyzed in terms of the three protonation state model for the enzyme (EH2 α EH α E). In the presence of L-Phe…

Purification and molecular characterization of the rhamnose binding lectin from sea bass (Dicentrarchus labrax) that agglutinate Gram positive and ne…

2013

Evolution and Immune Function of Fish Lectins

2016

Abstract Lectins are sugar-binding proteins widely distributed among animals, plants, and microbial taxon, involved in diverse biological processes. In both invertebrates and vertebrates, they play key roles in nonself recognition and immune responses, such as nonself recognition, inflammatory processes, and immunomodulation. In fish, many lectin families have been identified, and their tissue-specific expression and localization of the various lectin repertoires and their ligands are consistent with their distinct biological roles in innate and adaptive immunity. Here, we discuss the involvement of F-type lectins, rhamnose-binding lectins, galectins, and C-type lectins in pathogen recognit…

Theoretical studies of HIV-1 reverse transcriptase inhibition

2012

Computational methods for accurately calculating the binding affinity of a ligand for a protein play a pivotal role in rational drug design. We herein present a theoretical study of the binding of five different ligands to one of the proteins responsible for the human immunodeficiency virus type 1 (HIV-1) cycle replication; the HIV-1 reverse transcriptase (RT). Two types of approaches are used based on molecular dynamics (MD) simulations within hybrid QM/MM potentials: the alchemical free energy perturbation method, FEP, and the pathway method, in which the ligand is physically pulled away from the binding site, thus rendering a potential of mean force (PMF) for the binding process. Our com…

Immobilization of <i>Saccharomyces cerevisiae</i> Cells to Protein G-Sepharose by Cell Wall Engineering

2003

In this work, we explored the possibility of using the targeting of a heterologous protein to the cell wall of <i>Saccharomyces cerevisiae</i>, by fusing it to a cell wall protein, to construct yeast strains whose cells display on their surface proteins that bind to a matrix, so as to achieve the immobilization of the whole cells. With this aim, we created a gene fusion that comprises the region responsible for attachment of a cell wall protein to the cell wall, and the IgG binding region of staphylococcal protein A, and expressed it in the <i>mnn1mnn9</i> strain of <i>S. cerevisiae</i>. The surface display of the protein A-Icwp fusion protein was positiv…

Molecular Structure of the Arthropod Hemocyanins

1992

Hemocyanin is an extracellular, blue protein that occurs in high concentrations in the blood of many arthropods, including spiders, scorpions, horseshoe crabs, crustaceans, and at least two centipedes. Serving as an ### oxygen carrier, it is functionally equivalent to hemoglobin, but performs reversible oxygen binding between two copper ions. Hemocyanin is composed of a number of subunits that assemble in an extremely large macro-molecular entity. These particles, which are similar in size to viruses or ribosomes, exhibit a complex allosteric behavior during oxygen binding. There is growing evidence that this functional plasticity has evolved upon, and answers to, ecophysiological constrain…