title: A RuBisCO-mediated carbon metabolic pathway in methanogenic archaea.
abstract: Two enzymes are considered to be unique to the photosynthetic Calvin-Benson cycle: ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), responsible for CO2fixation, and phosphoribulokinase (PRK). Some archaea possess bona fide RuBisCOs, despite not being photosynthetic organisms, but are thought to lack PRK. Here we demonstrate the existence in methanogenic archaea of a carbon metabolic pathway involving RuBisCO and PRK, which we term 'reductive hexulose-phosphate' (RHP) pathway. These archaea possess both RuBisCO and a catalytically active PRK whose crystal structure resembles that of photosynthetic bacterial PRK. Capillary electrophoresis-mass spectrometric analysis of metabolites reveals that the RHP pathway, which differs from the Calvin-Benson cycle only in a few steps, is active in vivo. Our work highlights evolutionary and functional links between RuBisCO-mediated carbon metabolic pathways in methanogenic archaea and photosynthetic organisms. Whether the RHP pathway allows for autotrophy (that is, growth exclusively with CO2as carbon source) remains unknown.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan.|Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-Ku, Kobe 657-8501, Japan.
authors.forename: Takunari
authors.initials: T
authors.lastname: Kono
authors.affiliation: Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.
authors.forename: Sandhya
authors.initials: S
authors.lastname: Mehrotra
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Endo
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kizu
authors.affiliation: Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Matusda
authors.affiliation: Department of Geosciences, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan.|Research Institute of Green Science and Technology, Shizuoka University, Shizuoka 422-8529, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Mizohata
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Department of Chemical Science and Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan.
authors.forename: Akiho
authors.initials: A
authors.lastname: Yokota
authors.affiliation: Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Matsumura
authors.affiliation: Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-Ku, Kobe 657-8501, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ashida
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D019605:Euryarchaeota / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis; D010802:Phylogeny; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D002244:Carbon; D017853:Phosphotransferases (Alcohol Group Acceptor); C022390:phosphoribulokinase; D012273:Ribulose-Bisphosphate Carboxylase