Biomedical subjects

R J Vandenberg

Publications and source records attributed to R J Vandenberg.

22 records · Page 2Linked to original sources

PubMed1992

Distinct agonist- and antagonist-binding sites on the glycine receptor.

The distinction between receptor-binding sites for agonists and antagonists underpins the pharmacological differences between these two classes of ligands. In the glycine receptor, antagonist (strychnine) binding requires an interaction with residues Lys-200 and Tyr-202. We now demonstrate that the agonist-binding site of this receptor is located at the residue Thr-204. The agonist-binding site interaction is thus likely to be mediated by hydrogen bonding and not by ionic interactions. Our results demonstrate that, in contrast to other studies of ligand-gated ion channel receptors, agonist- and antagonist-binding sites are composed of distinct amino acid residues.

Alanine↗

PubMed1988

The role of Fc:Fc interactions in insoluble immune complex formation and complement activation.

The initial rate of formation of insoluble immune complexes from rabbit IgG and ovalbumin was approximately 12 times that for formation of F(ab')2-ovalbumin complexes. At low IgG concns, in the range 0.7-2.7 nM, the formation of insoluble immune complexes was characterised by a lag phase, especially for complexes formed in low antigen excess, compared to antibody excess. Guanidine HCl (at concns up to 0.5 M) and urea (at concns up to 1 M) decreased the initial rates of formation of IgG immune complexes more than F(ab')2 immune complexes. Pre-formed IgG immune complexes were solubilised at lower guanidine HCl concns than were F(ab')2 immune complexes. C1q enhanced the initial rate of formation of IgG immune complexes at C1q:IgG ratios up to 1:1. Higher C1q concns decreased the initial rate of formation of the complexes. Urea (1 M) blocked the C1q mediated enhancement of immune complex formation.

Animals↗

PubMed1987

Activation of the classical complement pathway by BioRex-70.

The cation exchange resin BioRex-70 was able to activate the classical complement pathway in human serum at 37 degrees C over the resin concentration range 0-5% (v/v). Using zymosan-treated human serum, it was found that the activation proceeded as far as complement protein C3.

Cation Exchange Resins↗

PubMed1986

Conformational changes in C1q upon binding to IgG oligomers.

The interaction between C1q and immune complexes is inhibited by 1-anilino-8-naphthalenesulfonate (ANS) in the concentration range of 2-4 mM. ANS binds to Clq with a 20-fold higher affinity than to IgG [(1986) Mol. Immunol. 23, 39-44] and therefore it is possible to label only C1q with ANS in the presence of IgG. Under such conditions no inhibition is observed. Addition of monomer IgG to a solution of C1q-bound ANS did not significantly alter the fluorescence of the ANS. However when oligomeric IgG was added there was a 2-fold increase in fluorescence over the same IgG concentration range. When C1q was pretreated with diethylpyrocarbonate there was little change in the fluorescence when IgG oligomers were added to C1q:ANS solutions. These results suggest that C1q undergoes conformational changes upon binding to IgG oligomers.

Anilino Naphthalenesulfonates↗