Conformational states of valinomycin and its complexes with alkali-metal cations in solutions

Ion transport across thin lipid membranes: a critical discussion of mechanisms in selected systems

“…The notation is defined in Ivanov et al (1969Ivanov et al ( , 1971. In order to get from an Aj to an A 2 conformation, three hydrogen bonds must be broken and then reformed.…”

“…turns, which they assert are a general feature of peptide structure. Ivanov et al (1971) changed from A x to A 2 on the basis of a more careful consideration of NMR coupling constants and a calculation of relative conformational energies. Mayers & Urry (1971) also supported their choice of A 2 with conformational energy calculations (see below).…”

“…However, the stability constant and solubility of the complex do, of course, differ from one solvent to the next. Ivanov et al (1969Ivanov et al ( , 1971) report conformations for free valinomycin based on IR, NMR, ORD and, recently, conformational energy calculations. The task of assigning conformations here is much more difficult since there is more than one form present.…”

“…Both Ivanov et al (1971) and Mayers & Urry (1971) • ' In' and ' out' refer to inside or outside of the ring. The notation is defined in Ivanov et al (1969Ivanov et al ( , 1971.…”

“…Both Ivanov et al (1971) and Mayers & Urry (1971) • ' In' and ' out' refer to inside or outside of the ring. The notation is defined in Ivanov et al (1969Ivanov et al ( , 1971. In order to get from an Aj to an A 2 conformation, three hydrogen bonds must be broken and then reformed.…”