title: Crystal structure of a conserved domain in the intermembrane space region of the plastid division protein ARC6.
abstract: The chloroplast division machinery is composed of numerous proteins that assemble as a large complex to divide double-membraned chloroplasts through binary fission. A key mediator of division-complex formation is ARC6, a chloroplast inner envelope protein and evolutionary descendant of the cyanobacterial cell division protein Ftn2. ARC6 connects stromal and cytosolic contractile rings across the two membranes through interaction with an outer envelope protein within the intermembrane space (IMS). The ARC6 IMS region bears a structurally uncharacterized domain of unknown function, DUF4101, that is highly conserved among ARC6 and Ftn2 proteins. Here we report the crystal structure of this domain from Arabidopsis thaliana ARC6. The domain forms an α/β barrel open towards the outer envelope membrane but closed towards the inner envelope membrane. These findings provide new clues into how ARC6 and its homologs contribute to chloroplast and cyanobacterial cell division.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.
authors.forename: Abhijith
authors.initials: A
authors.lastname: Radhakrishnan
authors.affiliation: Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.
authors.forename: Chih-Chia
authors.initials: CC
authors.lastname: Su
authors.affiliation: Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Osteryoung
authors.affiliation: Department of Chemistry, Iowa State University, Ames, Iowa, 50011.|Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry*; D029681:Arabidopsis Proteins / Q000737:chemistry*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: C502272:ARC6 protein, Arabidopsis; D029681:Arabidopsis Proteins
keywords: ARC6; DUF4101; chloplast; plastid division