Premium
Molecular determinants of external barium block in Shaker potassium channels
Author(s) -
Hurst Raymond S.,
Toro Ligia,
Stefani Enrico
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00516-9
Subject(s) - shaker , potassium channel , gating , biophysics , chemistry , block (permutation group theory) , mutant , barium , substitution (logic) , potassium channel blocker , blocking effect , potassium , stereochemistry , biochemistry , biology , physics , gene , geometry , inorganic chemistry , mathematics , computer science , quantum mechanics , vibration , programming language , psychology , developmental psychology , organic chemistry
Mutations in the outer pore region of Shaker K + channels ( T449 and D 447 ) can influence external Ba 2+ block. Substitution of T 449 by A, V or Y differentially reduced Ba 2+ block primarily by decreasing the blocking rate. Substitution of D 447 by N resulted in a non‐conducting channel with apparently normal gating currents. External Ba 2+ can speed the OFF gating current of a different non‐conducting mutant, W434F; this effect was markedly attenuated by the D447N substitution. These results suggest that D 447 contributes to an external Ba 2+ binding site while T 449 imposes a barrier to the access of that site.