Matrix protein in planar membranes: clusters of channels in a native environment and their functional reassembly.

摘要: Abstract Planar bilayers formed from Escherichia coli outer membrane vesicles exhibit conductance properties similar to those previously observed in reconstituted aggregates of matrix protein, the major protein. Discrete steps are observed, reflecting voltage-dependent transmembrane channels. These exist clusters which activated by voltage. After activation, channels close with increasing potentials and reopen reversibly at lower Depending on sign potential, two distinct closed states pores observed. Cooperative interactions, hysteresis effects, relaxation times, values channel depend cluster size. provide reference data for reconstitution function individual components. Planar were containing either solubilized protein a homogeneous trimeric state or bacterial glycolipid (lipopolysaccharide), both. Activation required presence formation clusters, leading closely resembling native membranes. At very low concentrations trimers, irreversible association lateral diffusion was Nearly quantitative recoveries allowed assignment three per trimer.