One challenge when working with traditional DIBMA is its sensitivity to the presence of ions inside the buffer / media. The reason for this is DIBMAs own charge that lets it interact with these ions. This leads to precipitation of DIBMA and therefore loss of its function. To overcome this issue we modified DIBMA to have a reduced charge to drastically reduce the affinity to the ions. This was achieved by adding Glucosamine or an amino-functionalized diol to DIBMA. This modified DIBMA can be used for experiments for which the presence of ions is crucial for their success.

Figure 1 shows the amount of membrane protein of interest that was stabilized by a DIBMALP in comparison to a construct using the detergent DDM. As it can clearly be seen DDM has way fewer specific bands at the desired kDA values of around 40-60 kDa.

Fig. 1: The yield of DIBMA-based nanodiscs compared to detergent micelles (e.g. DDM detergent)

An alternative to traditional DIBMAs and their sensitivity to the presence of ions inside a buffer, are our modified DIBMAs with added Glucosamine or amino-functionalized diol. As figure 2 indicates, the increased tolerance of Ca²⁺ is necessary. Normally DIBMA starts to precipitate in Ca²⁺ holding buffers at concentrations of around 25 mM. Using DIBMA-Glycerol this tolerance increases to 50 mM. There is no precipitate visible at the bottom of the tube. In comparison, normal DIBMA shows a visible precipitate at 25 mM. In terms of Mg²⁺ tolerance traditional DIBMA and the Glycerol-DIBMA both show a high tolerance above 50 mM.

Fig. 2: DIBMA precipitation in relation to the ion concentration. The shown concentrations start at 5 mM and are increasing in 5 mM steps up to 50 mM.