Cover Picture: Juxta-terminal Helix Unwinding as a Stabilizing Factor to Modulate the Dynamics of Transmembrane Helices (ChemBioChem 6/2016)
by Mortazavi, Armin; Rajagopalan, Venkatesan; Sparks, Kelsey A.; Greathouse, Denise V.; Koeppe II, Roger E.
The cover picture shows schematically the partial unwinding of 3–4 residues at each end of the tilted transmembrane helix of the designed peptide acetyl-GGAFF(LA)6LWLAGA-amide (F4,5GWALP23) in a lipid-bilayer membrane. The helix orientation and partial unwinding are revealed by solid-state deuterium NMR spectra of 2H-labeled alanine residues. The graph illustrates the dependence of the 2H quadrupolar splitting on the radial position of the deuterated alanine methyl group, with alanines 3 and 21 (red) clearly deviating from the curve defined by the core transmembrane helix. The fraying of helix ends might be vital for defining the dynamics and orientations of transmembrane helices in lipid-bilayer membranes. More information can be found in the communication by R. E. Koeppe II et al. on page 462 in Issue 6, 2016 (DOI: 10.1002/cbic.201500656).