Title
The IM30/Vipp1 C-terminus associates with the lipid bilayer and modulates membrane fusion
Author
Raoul Hennig, Ana West, Martina Debus, Michael Saur, Jürgen Markl, Jonathan N. Sachs, Dirk Schneider
Year
2016
Journal
Biochimica et Biophysica Acta (BBA) - Bioenergetics
Abstract
IM30/Vipp1 proteins are crucial for thylakoid membrane biogenesis in chloroplasts and cyanobacteria. A characteristic C-terminal extension distinguishes these proteins from the homologous bacterial PspA proteins, and this extension has been discussed to be key for the IM30/Vipp1 activity. Here we report that the extension of the SynechocystisIM30 protein is indispensable, and argue that both, the N-terminal PspA-domain as well as the C-terminal extension are needed in order for the IM30 protein to conduct its in vivofunction. In vitro, we show that the PspA-domain of IM30 is vital for stability/folding and oligomer formation of IM30 as well as for IM30-triggered membrane fusion. In contrast, the IM30 C-terminal domain is involved in and necessary to stabilize defined contacts to negatively charged membrane surfaces, and to modulate the IM30-induced membrane fusion activity. Although the two IM30 protein domains have distinct functional roles, only together they enable IM30 to work properly.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Biochemistry