title: Organization into Higher Ordered Ring Structures Counteracts Membrane Binding of IM30, a Protein Associated with Inner Membranes in Chloroplasts and Cyanobacteria.
abstract: The IM30 (inner membrane-associated protein of 30 kDa), also known as the Vipp1 (vesicle-inducing protein in plastids 1), has a crucial role in thylakoid membrane biogenesis and maintenance. Recent results suggest that the protein binds peripherally to membranes containing negatively charged lipids. However, although IM30 monomers interact and assemble into large oligomeric ring complexes with different numbers of monomers, it is still an open question whether ring formation is crucial for membrane interaction. Here we show that binding of IM30 rings to negatively charged phosphatidylglycerol membrane surfaces results in a higher ordered membrane state, both in the head group and in the inner core region of the lipid bilayer. Furthermore, by using gold nanorods covered with phosphatidylglycerol layers and single particle spectroscopy, we show that not only IM30 rings but also lower oligomeric IM30 structures interact with membranes, although with higher affinity. Thus, ring formation is not crucial for, and even counteracts, membrane interaction of IM30.
authors.affiliation: From the Institutes of Pharmacy and Biochemistry.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Heidrich
authors.affiliation: Physical Chemistry, and.
authors.forename: Verena
authors.initials: V
authors.lastname: Wulf
authors.affiliation: From the Institutes of Pharmacy and Biochemistry.
authors.forename: Raoul
authors.initials: R
authors.lastname: Hennig
authors.affiliation: Zoology, Johannes Gutenberg University, 55128 Mainz, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Saur
authors.affiliation: Zoology, Johannes Gutenberg University, 55128 Mainz, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Markl
authors.affiliation: Physical Chemistry, and.
authors.forename: Carsten
authors.initials: C
authors.lastname: Sönnichsen
authors.affiliation: From the Institutes of Pharmacy and Biochemistry, Dirk.Schneider@uni-mainz.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schneider
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D007700:Kinetics; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D020349:Surface Plasmon Resonance; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D050505:Mutant Proteins; D010715:Phosphatidylglycerols; C424449:VIPP1 protein, Synechocystis
keywords: PspA; Vipp1; chloroplast; cyanobacteria; gold nanoparticle; lipid binding protein; membrane biogenesis; oligomerization; thylakoid membrane; vesicle inducing protein 1