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. Author manuscript; available in PMC: 2009 Jan 31.
Published in final edited form as: Aquat Toxicol. 2007 Nov 1;86(2):121–130. doi: 10.1016/j.aquatox.2007.10.012

Figure 3.

Figure 3

Velocity sedimentation analysis of ligand binding ([3H]TCDD) by the four Atlantic salmon AHR2s: AHR2α, AHR2β, AHR2γ, and AHR2δ. For each protein, a diluted TnT reaction was incubated with [3H]TCDD (8 nM) (filled squares), and fractionated on 10–30% sucrose gradients. The binding of [3H]TCDD to unprogrammed lysate (UPL) was also assessed, as a measure of nonspecific binding (stars). The sedimentation markers [14C]ovalbumin (3.6 S) and [14C]catalase (11.3 S) eluted at fractions 3–4 and 15–16, respectively. Specific binding is the difference between total binding (radioligand binding to expressed protein) and nonspecific binding (radioligand binding to UPL). The amount of specific binding obtained was 10 fmol/reaction (α), 12.4 fmol/reaction (β), 37 fmol/reaction (γ) and 36 fmol/reaction (δ). It should be noted that all the reactions were done using the same amount of plasmid (1 ug) and that under those conditions the salmon AHR2 plasmids express different amounts of protein (as shown in Fig. 2).