Fluorine-NMR Reveals Conformational Differences Between ClC-ec1 Operating In Transporter And “Channel-like” Modes

Abstract

changes induced were large but two intracellular Cl induced the largest conformational change, repelling the side chain of E148 against the external channel wall. This distortion produced a pathway that had an area 2.4 times bigger than the one seen with COO À and no Cl. We anticipate that this larger pathway will allow Cl conduction easily. Our results imply that the combine actions of Cl and protonation of the E148 lateral chain are necessary to open the pore. Finally, the energy barriers that Cl faces during conduction strongly depend on structure, relative orientation, and chemical composition of the pore entryway. Supported by CONACyT grants 45928 (RG) and 79897 (JA).