Phe217 Regulates the Transfer of Allosteric Information across the Subunit Interface of the RecA Protein Filament

摘要: Abstract Background: ATP-mediated cooperative assembly of a RecA nucleoprotein filament activates the protein for catalysis DNA strand exchange. is classic allosterically regulated enzyme in that ATP binding results dramatic increase ssDNA affinity. This affinity almost exclusively from an rather than inherent monomeric DNA. Therefore, certain residues at subunit interface must play important role transmitting allosteric information across structure RecA. Results: Using electron microscopic analysis polymer formation absence DNA, we show while wild-type undergoes slight decrease length presence ATP, Phe217Tyr substitution ATP-induced assembly. Biosensor measurements reveal mutation increases interaction between subunits by more 250-fold. Conclusions: These studies represent first identification residue (Phe217) plays critical regulating flow throughout structure. We propose model which conformational changes occur upon are propagated through monomer, resulting insertion Phe217 side chain into pocket neighboring subunit. event serves as key step intersubunit communication leading to and high ssDNA.