DIBMA Protocol



  1. Dialyze 3 mL DIBMA in a 5-mL microdialysis capsule using a 3.5-MWCO dialysis membrane for 16 h against 1 L target buffer.
  2. Exchange buffer and dialyze again for 8 h. The volume will increase by about threefold. Check pH.
  3. Filter dialyzed DIBMA stock through a 0.22-μm syringe filter.
  4. Determine DIBMA concentration by refractometry using dn/dc = 1.346 M-1 , where c is DIBMA concentration based on Mn.
  5. Add DIBMA solution to cell lysate or membrane fraction and incubate at room temperature under gentle agitation for 16 h. Typical conditions are 2.5% (w/v) DIBMA for 42.5 mg mL-1 (wet mass/volume) E. coli membrane fraction.
  6. Remove unsolubilized membrane fragments by centrifugation at 100,000 g for 60 min (optional).
  7. DIBMALPs containing tagged protein can be subjected to further downstream purification.
  8. For SDS-PAGE, first extract polymer by CH3OH/CHCl3/H2O to avoid excessive smearing.
  9. For detailed instructions, see Oluwole et al., Angew. Chem. Int. Ed. 2017, 56, 1919–1924 (in particular, Supporting Information).