Figure 4. Analysis of activation‐independent crosslinking band at D78Bpa‐βarr1.

1. SDS–PAGE and immunoblots of immunoprecipitated samples. Sample 1 was immunoprecipitated without previous UV treatment. Sample 2 is the product of irradiation of sample 1. Sample 3 was treated with UV light before immunoprecipitation. All samples were run in parallel on the same gel.
2. Size exclusion chromatography (SEC) of Sample 3.
3. Western blot of the fractions eluted by SEC.
4. MALDI‐TOF analysis of the SEC fractions V_R2 and V_R3. The spectrum of sample V_R2 shows a [M + H]⁺ peak featuring twice the mass (˜ 108,000 Da) of the [M + H]⁺ peak of the βarr1 monomer (sample V_R3, ˜ 50,400 Da).