Atomic view of the histidine environment stabilizing higher-pH conformations of pH-dependent proteins

Céline Valéry (1, 2) , Stéphanie Deville-Foillard (3, 4) , Christelle Lefebvre (5) , Nuria Taberner (1) , Pierre Legrand (6) , Florian Meneau (6) , Cristelle Mériadec (5) , Camille Delvaux (4, 3) , Thomas Bizien (5) , Emmanouil Kasotakis (4, 3) , Carmen Lopez-Iglesias (7) , Andrew Gall (4, 3) , Stéphane Bressanelli (8, 4) , Marie-Hélène Le Du (9, 4) , Maité Paternostre (4, 8) , Franck Artzner (5)

1 IPSEN
2 UC-BIC - Biomolecular Interaction Centre [UC, Christchurch]
3 I2BC - Institut de Biologie Intégrative de la Cellule
4 IBITECS - Institut de Biologie et de Technologies de Saclay
5 IPR - Institut de Physique de Rennes
6 SSOLEIL - Synchrotron SOLEIL
7 Cryo-Electron Microscopy Unit, Scientific and Tecnological Centers
8 IMAPP - Interactions et mécanismes d’assemblage des protéines et des peptides
9 INTGEN - Enveloppe Nucléaire, Télomères et Réparation de l’ADN

External stimuli are powerful tools that naturally control protein assemblies and functions. For example, during viral entry and exit changes in pH are known to trigger large protein conformational changes. However, the molecular features stabilizing the higher pH structures remain unclear. Here we elucidate the conformational change of a self-assembling peptide that forms either small or large nanotubes dependent on the pH. The sub-angstrom high-pH peptide structure reveals a globular conformation stabilized through a strong histidine-serine H-bond and a tight histidine-aromatic packing. Lowering the pH induces histidine protonation, disrupts these interactions and triggers a large change to an extended b-sheet-based conformation. Re-visiting available structures of proteins with pH-dependent conformations reveals both histidine-containing aromatic pockets and histidine-serine proximity as key motifs in higher pH structures. The mechanism discovered in this study may thus be generally used by pH-dependent proteins and opens new prospects in the field of nanomaterials.

Domains: Life Sciences [q-bio]; Physics [physics]

Céline Valéry, Stéphanie Deville-Foillard, Christelle Lefebvre, Nuria Taberner, Pierre Legrand, et al.. Atomic view of the histidine environment stabilizing higher-pH conformations of pH-dependent proteins. Nature Communications, 2015, 6 (1), pp.7771. ⟨10.1038/ncomms8771⟩. ⟨cea-01201915⟩