Molecular basis of a lipid-PsbH protein interaction: a structural and “ab-initio” computational study

Dalibor Štys¹,², Žofie Sovová¹, Zbyněk Halbhuber¹, and Rüdiger Ettrich¹

1 Laboratories of High Performance Computing and Biomembranes, Institute of Physical Biology of the University of South Bohemia, and Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Zámek 136, 373 33 Nové Hrady, Czech Republic*

² Department of Autotrophic Microorganisms, Institute of Microbiology CAS, 37901 Trebon - Opatovicky mlyn, Czech Republic

Email: stys@jcu.cz

Keywords: PsbH protein, protein-lipid interaction, domain formation

Interaction of the PsbH protein of photosystem II was analysed by combination of CD and NMR spectroscopy and computer modeling. CD and NMR spectroscopy indicated that interactions to of PsbH to all bilayer-forming lipids, including those extracted directly from cyanobacterial thylakoid membranes, interact with PsbH non-specifically. The molecular dynamic calculation of PsbH-bilayer forming lipid interactions indicates that both salt-bridge formation and hydrogen bond formation in the lipid-water interface are feasible and stabilize fraction of at least 10 lipid molecules in the neighbourhood of the protein. This may lead to formation of lipid domains which were hypothesized to be involved in assembly of membrane protein complexes.