Biochemical characterization of the high affinity binding between the glycine receptor and gephyrin.

摘要: Abstract Gephyrin is an essential and instructive molecule for the formation of inhibitory synapses. binds directly to large cytoplasmic loop located between transmembrane helices three four β-subunit glycine receptor microtubules, thus promoting (GlyR) anchoring cytoskeleton clustering in postsynaptic membrane. Besides its structural role, gephyrin involved biosynthesis molybdenum cofactor that all molybdenum-dependent enzymes mammals. can be divided into N-terminal trimeric G domain a C-terminal E domain, which are connected by central linker region. Here we have studied vitro interaction domains with GlyR β-sub-unit (GlyRβ-loop). Binding exclusively mediated binding site was mapped one sub-domains (residues 496–654). By using isothermal titration calorimetry, high affinity (Kd = 0.2–0.4 μm) low 11–30 GlyRβ-loop found on holo-gephyrin respectively, stoichiometry two GlyRβ-loops per both cases. does not change oligomeric state either full-length or isolated domain.