Glycine Perturbs Local and Global Conformational Flexibility of a Transmembrane Helix

TY - JOUR

T1 - Glycine Perturbs Local and Global Conformational Flexibility of a Transmembrane Helix

AU - Högel, Philipp

AU - Götz, Alexander

AU - Kuhne, Felix

AU - Ebert, Maximilian

AU - Stelzer, Walter

AU - Rand, Kasper D

AU - Scharnagl, Christina

AU - Langosch, Dieter

PY - 2018/2/27

Y1 - 2018/2/27

N2 - Flexible transmembrane helices frequently support the conformational transitions between different functional states of membrane proteins. While proline is well known to distort and destabilize transmembrane helices, the role of glycine is still debated. Here, we systematically investigated the effect of glycine on transmembrane helix flexibility by placing it at different sites within the otherwise uniform leucine/valine repeat sequence of the LV16 model helix. We show that amide deuterium/hydrogen exchange kinetics are increased near glycine. Molecular dynamics simulations reproduce the measured exchange kinetics and reveal, at atomic resolution, a severe packing defect at glycine that enhances local hydration. Furthermore, glycine alters H-bond occupancies and triggers a redistribution of α-helical and 310-helical H-bonds. These effects facilitate local helix bending at the glycine site and change the collective dynamics of the helix.

AB - Flexible transmembrane helices frequently support the conformational transitions between different functional states of membrane proteins. While proline is well known to distort and destabilize transmembrane helices, the role of glycine is still debated. Here, we systematically investigated the effect of glycine on transmembrane helix flexibility by placing it at different sites within the otherwise uniform leucine/valine repeat sequence of the LV16 model helix. We show that amide deuterium/hydrogen exchange kinetics are increased near glycine. Molecular dynamics simulations reproduce the measured exchange kinetics and reveal, at atomic resolution, a severe packing defect at glycine that enhances local hydration. Furthermore, glycine alters H-bond occupancies and triggers a redistribution of α-helical and 310-helical H-bonds. These effects facilitate local helix bending at the glycine site and change the collective dynamics of the helix.

U2 - 10.1021/acs.biochem.7b01197

DO - 10.1021/acs.biochem.7b01197

M3 - Journal article

C2 - 29389107

SN - 0006-2960

VL - 57

SP - 1326

EP - 1337

JO - Biochemistry

JF - Biochemistry

IS - 8

ER -