Search results for "binding"

Computer Simulations of the Electric Interactions between the Phospholipid Head-Groups and Ionic Admixtures in the Membrane Surface

2001

Some phospholipids (e.g. lecithin) form a system of electric dipoles on the membrane surface layer. In the case of lecithin the positive dipole charge is located on the choline and the negative one on the phosphoric molecule group. These dipoles are arranged almost parallel to the membrane surface. Taking the dipole membrane structure as a base for further investigations, a computer model of the electrostatic interaction between the dipole system and the ionic admixture was investigated. The model presumes hexagonal centered or a rectangular flat geometry of the 121 dipoles distribution. The dipoles may rotate freely around round the motionless symmetry axis perpendicular to the system surf…

Total Synthesis of the Glycopeptide Recognition Domain of the P-Selectin Glycoprotein Ligand 1

2008

Glucosylation of Rho proteins by Clostridium difficile toxin B.

1995

TOXIN A and B, the major virulence factors of Clostridium difficile, are the causative agents of antibiotic-associated pseudomembran-ous colitis. In cultured cell lines their potent cytotoxicity results from their ability to induce disaggregation of the microfilament cytoskeleton1,2. Toxin B acts on the low-molecular-mass GTPase Rho A3,4, which is involved in the regulation of the actin cytoskeleton. We report here that toxin B catalyses the incorporation of up to one mole of glucose per mole of RhoA at the amino acid thre-onine at position 37. The modification was identified and localized by tandem electrospray mass spectrometry. UDP-glucose selectively serves as cosubstrate for the monogl…

JNK phosphorylation relieves HDAC3-dependent suppression of the transcriptional activity of c-Jun

2003

The AP-1 transcription factor c-Jun is a prototypical nuclear effector of the JNK signal transduction pathway. The integrity of JNK phosphorylation sites at serines 63/73 and at threonines 91/93 in c-Jun is essential for signal-dependent target gene activation. We show that c-Jun phosphorylation mediates dissociation of an inhibitory complex, which is associated with histone deacetylase 3 (HDAC3). The subsequent events that ultimately cause increased mRNA synthesis are independent of c-Jun phosphorylation and its interaction with JNK. These findings provide an 'activation by de-repression' model as an explanation for the stimulatory function of JNK on c-Jun.

Ras, Rap, and Rac Small GTP-binding Proteins Are Targets for Clostridium sordellii Lethal Toxin Glucosylation

1996

Lethal toxin (LT) from Clostridium sordellii is one of the high molecular mass clostridial cytotoxins. On cultured cells, it causes a rounding of cell bodies and a disruption of actin stress fibers. We demonstrate that LT is a glucosyltransferase that uses UDP-Glc as a cofactor to covalently modify 21-kDa proteins both in vitro and in vivo. LT glucosylates Ras, Rap, and Rac. In Ras, threonine at position 35 was identified as the target amino acid glucosylated by LT. Other related members of the Ras GTPase superfamily, including RhoA, Cdc42, and Rab6, were not modified by LT. Incubation of serum-starved Swiss 3T3 cells with LT prevents the epidermal growth factor-induced phosphorylation of m…

NG2 regulates directional migration of oligodendrocyte precursor cells via Rho GTPases and polarity complex proteins.

2013

The transmembrane proteoglycan NG2 is expressed by oligodendrocyte precursor cells (OPC), which migrate to axons during developmental myelination and remyelinate in the adult after migration to injured sites. Highly invasive glial tumors also express NG2. Despite the fact that NG2 has been implicated in control of OPC migration, its mode of action remains unknown. Here, we show in vitro and in vivo that NG2 controls migration of OPC through the regulation of cell polarity. In stab wounds in adult mice we show that NG2 controls orientation of OPC toward the wound. NG2 stimulates RhoA activity at the cell periphery via the MUPP1/Syx1 signaling pathway, which favors the bipolar shape of migrat…

Receptor Binding Properties of the New and Specific Thromboxane Receptor Antagonist Bay U 3405

1992

Human platelet membranes were used to characterize the receptor binding properties of the specific thromboxane receptor antagonist 3H-SQ 29548 and the displacement of 3H-SQ 29548 from its binding site by the new thromboxane receptor antagonist Bay u 3405. The specific binding of 3H-SQ 29548 was saturable with an association rate constant of 1 x 10(-11) mol-1 min-1 and a dissociation rate constant of 0.032 min-1. Nonspecific binding of 3H-SQ 29548 was below 10%. When Scatchard plot analysis was performed on equilibrium saturation binding the kD was 69 nmol/l and the Bmax was calculated as 3.9 pmol/mg membrane protein. 3H-SQ 29548 was dose dependently displaced from its binding site by additi…

Correction to “Self-Consistent Charge Density-Functional Tight-Binding Parameterization for Pt–Ru Alloys”

2018

Tight-Binding Simulations of Nanowires

2015

Ferricytochrome c encapsulated in silica hydrogels: correlation between active site dynamics and solvent structure.

2003

Ferricytochrome c encapsulated in silica hydrogels has been prepared by the sol-gel technique following, with some modifications, the procedure originally developed by Ellerby et al. (Science 255 1113 (1992)). A suitable preparation of hydrogels enables having both 'wet' and 'dry' samples. Wet samples have a high water content: as the temperature is lowered below approximately 260 K, water freezes and the samples crack. On the contrary, dry samples have a low water content (hydration h approximately equal 0.35): in these conditions water does not freeze even at cryogenic temperatures and the samples remain transparent and non-cracking. The dynamics of ferricytochrome c and its dependence on…