Figure S8. PolyP binding may induce oligomerization of CtCHAD.
SEC and RALS analysis of CtCHAD in complex with polyP. (A) RALS traces of CtCHAD in the presence (red) and absence (blue) of 1 mM polyP (average chain length ∼30 Pi units). Indicated oligomeric states are calculated based on CtCHAD, as shown in (B). (B) RALS traces (blue) and extrapolated molecular weight (black) of the two peaks of CtCHAD. Retention volumes and calculated molecular weights are shown alongside. In the absence of polyP, CtCHAD forms a dimer (∼90%) and a tetramer (∼10%). The theoretical molecular weight of monomeric CtCHAD is 36,194 D. (C) Putative tetrameric and dimeric assemblies for CtCHAD based on crystal packing analysis as implemented in the program PISA (Krissinel & Henrick, 2007). Shown are molecular surfaces of a CtCHAD tetramer (left) and dimer (right) in two orientations, respectively. Note that the position of the central cavities in the tetramer and the polyP-binding surfaces in the dimer could allow for the cooperative binding of long-chain polyPs.