Carbonic anhydrase subunits form a matrix-exposed domain attached to the membrane arm of mitochondrial complex I in plants
Creators: name: Sunderhaus, Stephanie
name: Dudkina, Natalya V.
name: Jänsch, Lothar
name: Klodmann, Jennifer
name: Heinemeyer, Jesco
name: Perales, Mariano
name: Zabaleta, Eduardo
name: Boekema, Egbert J.
name: Braun, Hans-Peter
Publisher: name: Bethesda, Md. : ASBMB Publications
Year: 2006
Subjects: subject: Biological membranes
subject: Carbonates
subject: Electron microscopy
subject: Liquid chromatography
subject: Mass spectrometry
subject: Proteins
subject: Carbonate extraction experiments
subject: Carbonic anhydrase
subject: Green alga Polytomella
subject: Isolated mitoplasts
subject: Mitochondrial complex I
subject: Plants (botany)
subject: calnexin
subject: carbonate dehydratase
subject: membrane protein
subject: mitochondrial complex i enzyme
subject: mitochondrial enzyme
subject: reduced nicotinamide adenine dinucleotide dehydrogenase (ubiquinone)
subject: succinate dehydrogenase (ubiquinone)
subject: unclassified drug
subject: mitochondrial protein
subject: peptide hydrolase
subject: protein subunit
subject: Arabidopsis
subject: article
subject: controlled study
subject: electron microscopy
subject: enzyme analysis
subject: enzyme structure
subject: enzyme subunit
subject: green alga
subject: liquid chromatography
subject: mitochondrial membrane
subject: mitochondrion
subject: nonhuman
subject: priority journal
subject: tandem mass spectrometry
subject: cell culture
subject: chemistry
subject: enzymology
subject: metabolism
subject: protein quaternary structure
subject: protein tertiary structure
subject: transmission electron microscopy
subject: ultrastructure
subject: Chlorophyta
subject: Polytomella
subject: Algae, Green
subject: Carbonic Anhydrases
subject: Cells, Cultured
subject: Electron Transport Complex I
subject: Membrane Proteins
subject: Microscopy, Electron, Transmission
subject: Mitochondria
subject: Mitochondrial Proteins
subject: Peptide Hydrolases
subject: Protein Structure, Quaternary
subject: Protein Structure, Tertiary
subject: Protein Subunits
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: Complex I of Arabidopsis includes five structurally related subunits representing γ-type carbonic anhydrases termed CA1, CA2, CA3, CAL1, and CAL2. The position of these subunits within complex I was investigated. Direct analysis of isolated subcomplexes of complex I by liquid chromatography linked to tandem mass spectrometry allowed the assignment of the CA subunits to the membrane arm of complex I. Carbonate extraction experiments revealed that CA2 is an integral membrane protein that is protected upon protease treatment of isolated mitoplasts, indicating a location on the matrix-exposed side of the complex. A structural characterization by single particle electron microscopy of complex I from the green alga Polytomella and a previous analysis from Arabidopsis indicate a plant-specific spherical extra-domain of about 60 Å in diameter, which is attached to the central part of the membrane arm of complex I on its matrix face. This spherical domain is proposed to contain a heterotrimer of three CA subunits, which are anchored with their C termini to the hydrophobic arm of complex I. Functional implications of the complex I-integrated CA subunits are discussed.