Bovine pancreatic trypsin inhibitor as a probe of large conductance Ca(2+)-activated K+ channels at an internal site of interaction.
Bovine pancreatic trypsin inhibitor (BPTI) is a 58 residue protein whose binding to various serine proteases has been extensively studied by X-ray crystallography. We have found that BPTI also binds to an intracellular site associated with the large conductance Ca(2+)-activated K+ channel, as detected by the production of subconductance events in single channels incorporated into planar lipid bilayers. BPTI is highly homologous to a family of mamba snake dendrotoxin proteins that inhibit various K+ channels at an extracellular site. BPTI thus provides a useful model system to explore basic mechanisms underlying protein-channel interactions.
Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510.
E
E
Moczydlowski
G W
GW
Moss
K J
KJ
Lucchesi
D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D004546:Elapid Venoms / Q000737:chemistry / Q000494:pharmacology; D004553:Electric Conductivity; D008956:Models, Chemical; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000187:drug effects*
D004546:Elapid Venoms; D015221:Potassium Channels; C020273:dendrotoxin; D007611:Aprotinin; D002118:Calcium