Bion-binding proteins identified by LC-MS/MS and ranked by spectral counting.

Bions were prepared by adding CaCl2, MnCl2, SrCl2, or BaCl2 at a final concentration of 10 mM, or MgCl2 at 20 mM in DMEM containing 5% FBS. Na2HPO4 at 10 mM was then added (in a final volume of 1 ml). Following incubation in cell culture conditions overnight, bions were washed and then treated with 0.1 mM EDTA to help release the bound proteins. Proteomic analysis was performed using LC-MS/MS as described in Materials and Methods. Spectral counting values were normalized by multiplying each number of spectra by the average of total spectra count for the five samples shown, and then dividing by the sum of spectra for the corresponding sample. MW, molecular weight in kDa.