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At least 163 records · Page 9Linked to original sources
PubMed1990

Drug interactions involving immunologic agents. Part I. Vaccine-vaccine, vaccine-immunoglobulin, and vaccine-drug interactions.

Information about immunologic drug interactions is needed by pharmacists to make rational drug-use decisions. Previously, reports of interactions involving vaccines, immune globulins, and immunodiagnostic reagents were widely dispersed. In this two-part review article, over 50 individual and categorical interactions are described, as are dozens of vaccine-vaccine and vaccine-immunoglobulin, and vaccine-drug interactions are reviewed in this first part. Vigilance by all pharmacists is needed to detect previously unreported immunologic drug interactions and to further assess known interactions.

Drug Interactions↗
PubMed2001

Stabilization of alpha-helix structure by polar side-chain interactions: complex salt bridges, cation-pi interactions, and C-H em leader O H-bonds.

It is generally understood that helical proteins are stabilized by a combination of hydrophobic and packing interactions, together with H-bonds and electrostatic interactions. Here we show that polar side-chain interactions on the surface can play an important role in helix formation and stability. We review studies on model helical peptides that reveal the effect of weak interactions between side chains on helix stability, focusing on some nonclassical side-chain-side-chain interactions: complex salt bridges, cation-pi, and C-H em leader O H-bonding interactions. Each of these can be shown to contribute to helix stability, and thus must be included in a comprehensive catalogue of helix stabilizing effects. The issue of the structure of the unfolded states of helical peptides is also discussed, in the light of recent experiments showing that these contain substantial amounts of polyproline II conformation.

Amino Acid Sequence↗
PubMedDate not supplied

Delineating protein-protein interactions via biomolecular interaction analysis-mass spectrometry.

The utility of biomolecular interaction analysis-mass spectrometry (BIA/MS) in screening for protein-protein interactions was explored in this work. Experiments were performed in which proteins served as ligands for screening of possible interactions with other proteins from human plasma and urine. The proteins utilized were beta-2-microglobulin, cystatin C (cysC), retinol binding protein (RBP), transthyretin (TTR), alpha-1-microglobulin, C-reactive protein, transferrin and papain. The immobilization of functionally active proteins was confirmed via interactions with antibodies to the corresponding proteins. Various dilutions of human urine and plasma were injected over the protein-derivatized surfaces. It was observed that the urine injections generally yielded smaller SPR responses than those observed after the plasma injections. The BIA/MS experiments did not reveal novel protein-protein interactions, although several established interactions (such as those between RBP and TTR, and cysC and papain) were validated. Few protein ligand deficiencies (such as truncations) leading to false negative and false positive BIA/MS results were also discovered.

Humans↗
PubMed1975

Drug-biomolecule interactions: interactions of mononucleotides and polybasic amino acids.

Histones and ribosomal proteins are basic proteins that participate in gene regulation and protein synthesis, respectively. How these proteins interact with nucleic acids is not yet clear, although specificities in these interactions have been observed. Study of the interaction of mononucleotides with basic polyamino acids is one approach to understanding such interactions. The results of studies with the mononucleotides can help elucidate the normal molecular processes in biological systems and also shed light on some effects of drugs, such as puromycin and tubericidin, that are nucleotide derivatives. A review of studies on the interaction of mononucleotides and basic polyamino acids such as polylysine and polyarginine is presented. In addition, a short review of the self-associative properties of mononucleotides is given. Studies of the mononucleotide-polyamino acid interaction have involved a wide variety of techniques including equilibrium dialysis, NMR, optical rotatory dispersion, circular dichroism, and precipitate analysis.

Amino Acids↗
PubMed1975

Drug-biomolecule interactions: interaction of gentamicin with lipid monomolecular films.

The interaction of gentamicin with monomolecular films of a series of biologically important lipids spread on an aqueous buffered subphase was studied. The surface pressure, pi, of these films was determined by the Wilhelmy plate method as a function of surface area, A, and pi-A curves were constructed. Changes in the pi-A characteristics in the presence of gentamicin were used as a measure of antibiotic-film interaction. No interaction was observed between gentamicin and films of cholesterol, egg lecithin, dipalmitoyl lecithin, phosphatidyl ethanolamine, stearyl alcohol, and bovine ceramides at all pH values studied. Stearic acid films showed no interaction with gentamicin at pH 5. At pH 7 and 8, a small increase in pressure (approximately 3 dynes/cm) was noted. A dramatic increase in surface pressure was observed in the presence of stearyl aldehyde films ranging from approximately 9 dynes/cm at pH 7,2 to 23 dynes/cm at pH 8.4. This effect was attributed to a Schiff-base reaction between the nonprotonated primary amino groups on the gentamicin molecule and the stearyl aldehyde. Further evidence was reported by the fact that the addition of glucose (which has been reported to participate in Schiff-base formation with amines) to the subphase inhibited the stearyl aldehyde-gentamicin interaction. Sucrose did not show a corresponding effect. The addition of sodium bisulfite, which reacts with aldehydes to form alpha-hydroxysulfonic acid, also inhibited the gentamicin-stearyl aldehyde interaction. It is postulated that Schiff-base formation is a step in the in vivo transport of gentamicin across the membrane of sensitive organisms.

Chemical Phenomena↗
PubMed1995

Addition of side chain interactions to modified Lifson-Roig helix-coil theory: application to energetics of phenylalanine-methionine interactions.

We introduce here i, i + 3 and i, i + 4 side chain interactions into the modified Lifson-Roig helix-coil theory of Doig et al. (1994, Biochemistry 33:3396-3403). The helix/coil equilibrium is a function of initiation, propagation, capping, and side chain interaction parameters. If each of these parameters is known, the helix content of any isolated peptide can be predicted. The model considers every possible conformation of a peptide, is not limited to peptides with only a single helical segment, and has physically meaningful parameters. We apply the theory to measure the i, i + 4 interaction energies between Phe and Met side chains. Peptides with these residues spaced i, i + 4 are significantly more helical than controls where they are spaced i, i + 5. Application of the model yields delta G for the Phe-Met orientation to be -0.75 kcal.mol-1, whereas that for the Met-Phe orientation is -0.54 kcal.mol-1. These orientational preferences can be explained, in part, by rotamer preferences for the interacting side chains. We place Phe-Met i, i + 4 at the N-terminus, the C-terminus, and in the center of the host peptide. The model quantitatively predicts the observed helix contents using a single parameter for the side chain-side chain interaction energy. This result indicates that the model works well even when the interaction is at different locations in the helix.

Amino Acid Sequence↗
PubMed2006

Stereochemistry of guanidine-metal interactions: implications for L-arginine-metal interactions in protein structure and function.

The geometries of 150 guanidine-metal ion interactions retrieved from crystal structures deposited in the Cambridge Structural Database have been analyzed. Metal ions exhibit a preference for anti coordination stereochemistry in the plane of the unprotonated guanidine group, usually in chelate complexes with a diguanidine moiety, but syn-oriented interactions are occasionally found for single guanidine-metal interactions. Three L-arginine-metal coordination interactions are found in metalloenzyme structures deposited in the Protein Data Bank: biotin synthase from E. coli, His-67 --> Arg human carbonic anhydrase I, and inactivated B. caldovelox arginase complexed with L-arginine. In these proteins, L-arginine-metal coordination adopts syn/out-of-plane and anti/in-plane coordination stereochemistry. The implications of these results for L-arginine-metal interactions in protein structure and function are discussed. Although such interactions are rare, this analysis serves as a useful reference point for the growing interest in enzymes containing L-arginine residues that function as general bases or metal ligands.

Arginine↗
PubMed2001

RNA-RNA noncovalent interactions investigated by microspray ionization mass spectrometry.

Electrospray ionization mass spectrometry is playing an increasing role in the study of noncovalent interactions involving biomolecules. RNA-RNA complexes are important in many areas of biology, including RNA catalysis, RNA splicing, ribosome function, and gene regulation. Here, microelectrospray mass spectrometry (microESI-MS) is used to study noncovalent base-pairing interactions between RNA oligonucleotides, an area not previously explored by this technique. Using a set of complementary RNA oligonucleotides, we demonstrate the formation of the expected double-helical RNA complexes composed of three distinct oligonucleotides. The ability to study specific RNA noncovalent interactions by microESI-MS has the potential to provide a unique method by which to analyze and assign precise molecular masses to RNA-RNA complexes.

Base Sequence↗
PubMed2002

In vivo selectively infective phage as a tool to detect protein interactions: evaluation of a novel vector system with yeast Ste7p-Fus3p interacting proteins.

The selectively infective phage (SIP) approach allows rapid identification of interacting proteins by linking protein-protein interaction to phage infectivity. Infection of E. coli by filamentous phage depends on viral g3p. This protein consists of three domains, N1, N2 and CT. Phages lacking the N1 domain are non-infective unless a bait (X)-prey (Y) interaction links it to phage anchored N2-CT domains. We have developed all the vectors required for an in vivo selectively infective phage strategy (SIP). This includes a bait vector, pG3N1, a prey vector, pHOS41, and a gene III deletion helper phage, HPd3. The bait vector pG3N1 allows expression of a bait protein (X) fused to the C-terminus of the N1 domain. The prey vector pHOS41 allows expression of prey (Y) proteins, fused to the N-terminus of the N2-CT domains. The gene III deletion helper phage delivers all phage proteins necessary for phage production, except g3p. Escherichia coli transformed with these three vectors produces non-infective phages unless a bait-prey interaction links the g3p domains. Fus3p and Ste7p, two proteins from the Saccharomyces cerevisiae pheromone-responsive pathway have been cloned to evaluate the SIP strategy. The presence of the interacting N1-Fus3p adapter increased the infectivity of Ste7p-N2-CT phages approximately 1400-fold, which makes SIP a promising technology for the detection and further investigation of interacting proteins.

Capsid Proteins↗
PubMed1996

CAM-FGF receptor interactions: a model for axonal growth.

A number of experimental paradigms have been used to demonstrate that NCAM, N-cadherin, and L1 stimulate axonal growth. The molecular basis of this response has been extensively studied and a range of agents that inhibit neurite outgrowth stimulated by the above CAMs, but not integrins, have now been identified. These studies pointed to the activation of a tyrosine kinase-PLCgamma cascade as being important for the neurite outgrowth responses stimulated by all three CAMs, and this was substantiated by the identification of agents that could activate the cascade and mimic the growth response. In this review we will suggest that the neurite growth response stimulated by these CAMs is mediated by activation of the fibroblast growth factor receptor (FGFR) in neurons and that this results in the recruitment and activation of PLCgamma via interactions of its SH2 domain with the activated receptor. In this context the key events downstream from activation of PLCgamma required for neurite growth appear to be the conversion of diacylglycerol (DAG) to arachidonic acid (AA) via DAG lipase activity, followed by an increased influx of calcium into the neurons. The evolutionary conservation of putative binding motifs between the above CAMs and the FGFR suggests that activation of the FGFR-PLCgamma cascade by the CAMs might involve a direct CAM-FGFR interaction. The identification of the binding motifs also allows for predictions to be made concerning whether other CAMs might directly interact with the FGFR.

Amino Acid Sequence↗
PubMed1996

Interaction between the cytoplasmic domains of HIV-1 Vpu and CD4: role of Vpu residues involved in CD4 interaction and in vitro CD4 degradation.

The Vpu and CD4 cytoplasmic domains were found, by using a two-hybrid assay in yeast, to interact in the absence of their membrane anchor domains. Studies on several deletion and point mutants revealed that the overall structure of the Vpu cytoplasmic domain is required for this interaction. The Vpu amino acid residues involved in the interaction with CD4 were identified. Deletion of the C-terminal residues of Vpu, required for CD4 degradation, as well as the double mutation on the casein kinase II phosphorylation sites S52N-S56N, also involved in CD4 degradation, resulted in the loss of interaction with CD4 and in the inability to induce CD4 degradation. These results suggest that the ability of Vpu to mediate the degradation of CD4 is linked to its capacity to physically interact with CD4. However, additional mutagenesis on the S52 site revealed that the interaction between the cytoplasmic domains of Vpu and CD4 is not sufficient for in vitro Vpu-mediated CD4 degradation.

Amino Acid Sequence↗
PubMed1999

Potyvirus helper component-proteinase self-interaction in the yeast two-hybrid system and delineation of the interaction domain involved.

Using the yeast two-hybrid system, a screen was performed for possible interactions between the proteins encoded by the 5' region of potyviral genomes [P1, helper component-proteinase (HC-Pro), and P3]. A positive self-interaction involving HC-Pro was detected with lettuce mosaic virus (LMV) and potato virus Y (PVY). The possibility of heterologous interaction between the HC-Pro of LMV and of PVY was also demonstrated. No interaction involving either the P1 or the P3 proteins was detected. A series of ordered deletions from either the N- or C-terminal end of the LMV HC-Pro was used to map the domain involved in interaction to the 72 N-terminal amino acids of the protein, a region known to be dispensable for virus viability but necessary for aphid transmission. A similar but less detailed analysis mapped the interacting domain to the N-terminal half of the PVY HC-Pro.

Binding Sites↗
PubMed1980

Genetic interactions in the control of mitochondrial function in Paramecium. II. Interactions between nuclear and mitochondrial genomes.

In an attempt to understand the genetic interactions between nuclear and mitochondrial genomes leading to mitochondrial biogenesis, different combinations of known nuclear and mitochondrial mutations have been constructed by microinjection. Eleven different tetrazolium resistant mutant strains, many clearly affecting mitochondrial function, were injected with mitochondria from four different erythromycin resistant mitochondrial mutants. Cases were found in which mutant mitochondria were unable to replicate in tetrazolium resistant mutants. The successful mitochondrial transfers were characterized for growth rate, temperature and cold sensitivity. Several selected combinations were characterised also for cytochrome spectra and cyanide resistance. Many different phenotypes were produced by the interaction of the different nuclear and mitochondrial mutations. These ranged from a positive interaction in which mutant mitochondria were selected by a nuclear mutant in preference to wild-type, through apparent absence of interaction, to negative interaction in which the mitochondrial-nuclear combination was temperature sensitive even though both 'parents' were thermoresistant. The possible molecular basis of these interactions is discussed.

Animals↗