The cross-linking reagent dimethyl suberimate modifies the target size of an insect nervous system nicotinic acetylcholine receptor

Radiation inactivation and simple target theory were employed to determine the molecular weight of an insect CNS α-bungarotoxin binding component in the presence and absence of a cross-linking reagent, dimethyl suberimate. In the presence of the cross-linker, the number of binding sites decreased, and the apparent molecular weight (236,000) was approximately double the control value (112,000). This, together with sedimentation data, suggests that the lower value represents only a portion of the insect nicotinic receptor molecule. A model is presented to account for the increase in target size and reduction in the number of α-[3H]bungarotoxin binding sites in the presence of dimethyl suberimate. © 1988.