Single channel recordings of alpha-hemolysin reconstituted in S-layer-supported lipid bilayers

Previous studies demonstrated that lipid membranes attached to a proteinaceous crystalline surface-layer (S-layer) revealed a prolonged lifetime and showed a reduced tendency to rupture in the presence of membrane active molecules. In addition, comparative studies on folded and S-layer-supposrted lipid membranes (SsLM) revealed an uniform capacitance of 0.64+/-0.04 muF/cm(2) for both composite membranes. In the present study, the feasibility to reconstitute the channel-forming protein alpha-hemolysin (alphaBL) into SsLM at single channel resolution was investigated. Single alphaHL channels could be recorded and the intrinsic properties like unitary conductance, current-voltage characteristics, and closure was found to be similar at both membranes. Thus, the tightly attached S-layer allowed complete reconstitution of alphaHL channels in SsLM. (C) 2002 Elsevier Science B.V. All rights reserved.