tailieunhanh - Báo cáo khoa học: Post-translational modifications in the active site region of methyl-coenzyme M reductase from methanogenic and methanotrophic archaea

Methyl-coenzyme M reductase (MCR) catalyzes the methane-forming step in methanogenic archaea. Isoenzyme I from Methanothermobacter marbur-gensis 2 was shown to contain a thioxo peptide bond and four methylated amino acids in the active site region. | ỊFEBS Journal Post-translational modifications in the active site region of methyl-coenzyme M reductase from methanogenic and methanotrophic archaea Jorg Kahnt1 Barbel Buchenau1 Felix Mahlert1 Martin Kruger2 Seigo Shima1 and Rudolf K. Thauer1 1 Max Planck Institute for TerrestrialMicrobiology Marburg Germany 2 Bundesanstalt fur Geowissenschaften und Rohstoffe Hannover Germany Keywords methanogenic archaea methanotrophic archaea methylated amino acids methylcoenzyme M reductase thioxo peptides Correspondence R. Thauer Max-Planck-Institute fur terrestrische Mikrobiologie Karl-von-Frisch-Strasse D-35043 Marburg Germany Fax 49 6421 178109 Tel 49 6421 178101 E-mail thauer@ Website http Methyl-coenzyme M reductase MCR catalyzes the methane-forming step in methanogenic archaea. Isoenzyme I from Methanothermobacter marbur-gensis was shown to contain a thioxo peptide bond and four methylated amino acids in the active site region. We report here that MCRs from all methanogens investigated contain the thioxo peptide bond but that the enzymes differ in their post-translational methylations. The MS analysis included MCR I and MCR II from Methanothermobacter marburgensis MCR I from Methanocaldococcus jannaschii and Methanoculleus thermophilus and MCR from Methanococcus voltae Methanopyrus kandleri and Methanosarcina barkeri. Two MCRs isolated from Black Sea mats containing mainly methanotrophic archaea of the ANME-1 cluster were also analyzed. Received 11 June 2007 revised 23 July 2007 accepted 26 July 2007 doi Methane is formed in methanogenic archaea from methyl-coenzyme M by reduction with coenzyme B. This reaction is catalyzed by methyl-coenzyme M reductase MCR . The 300 kDa enzyme is composed of three different subunits in an a2b2c2 arrangement and contains 2 mol of the nickel tetrapyrrole coenzyme F430 tightly bound. The prosthetic group has to be in the Ni I oxidation state for the enzyme to be .