The S100 family is a group of dimeric, calcium-binding proteins which have been found to be overexpressed in several types of cancer. S100 proteins bind to the Cterminal region (293-393) of p53, the most critical tumor suppressor involved in apoptosis, cell cycle arrest and DNA repair. Since S100 is dimeric and the C-terminus of p53 encompasses a tetramerization domain, the potential range of complexes incorporating p53 and S100 is large.
The p53 variants have a large fraction of intrinsically disordered structure and do not elute according to globular protein standards in size-exclusion chromatography (SEC). However, multi-angle light scattering determines molecular mass from first principles and does not depend on SEC column calibration standards. Combining SEC with static multi-angle light scattering (SEC-MALS) provides an ideal system to study the complex formation of S100 proteins and p53; it determines the molecular weight of the complexes independently of protein standards and retention time, under native buffer conditions.
We utilized SEC-MALS to investigate how S100 proteins bind to p53 in its different oligomeric states, using monomeric (L344P) and dimeric (L344A) p53 mutants.
