Abstract 2614 Utilizing Cleavable Crosslinkers to Determine the CowN-MoFeP Binding Site

I-TASSER and CHARMM-GUI under biological conditions suggest active motion and instability of the CTD over the entire time-period sampled.Additional simulations using enhanced sampling techniques will compare differences in protein conformation over long time-frames with Ser to Glu mutations at consensus phosphorylation sites (amino acid positions, 879, 893, 938, 950, 965).Our lab has also expressed the Srs2 CTD (783-1174) protein fragment in E. coli followed by isolation and characterization with fluorescence quenching analysis to show extensive exposure of the single Trp (812) to quencher agents.This behavior is consistent with IDR properties and active motion of the CTD.Four additional CTD phosphomimetic mutants (Ser to Glu at the above sites) have been expressed and isolated.Fluorescence quenching studies with these mutants are planned in the near future.