title: Purification and characterization of azurin from the methylamine-utilizing obligate methylotroph  Methylobacillus flagellatus  KT.
abstract: Methylamine dehydrogenase (MADH) and azurin were purified from the periplasmic fraction of the methylamine-grown obligate methylotroph Methylobacillus flagellatus KT. The molecular mass of the purified azurin was 16.3 kDa, as measured by SDS-PAGE, or 13 920 Da as determined by MALDI-TOF mass spectrometry. Azurin of M. flagellatus KT contained 1 copper atom per molecule and had an absorption maximum at 620 nm in the oxidized state. The redox potential of azurin measured at pH 7.0 by square-wave voltammetry was +275 mV versus normal hydrogen electrode. MADH reduced azurin in the presence of methylamine, indicating that this cupredoxin is likely to be the physiological electron acceptor for MADH in the electron transport chain of the methylotroph. A scheme of electron transport functioning in M. flagellatus KТ during methylamine oxidation is proposed.
authors.affiliation: Department of Microbiology, MV Lomonosov Moscow State University, 1/12 Lenin's Hills, Moscow 119991, Russian Federation. dinarieva@mail.ru
authors.forename: Tatiana Y
authors.initials: TY
authors.lastname: Dinarieva
authors.forename: Stanislav A
authors.initials: SA
authors.lastname: Trashin
authors.forename: Jörg
authors.initials: J
authors.lastname: Kahnt
authors.forename: Arkady A
authors.initials: AA
authors.lastname: Karyakin
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Netrusov
mesh_terms: D001400:Azurin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D008744:Methylamines / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D020631:Methylobacillus / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000032:analysis / Q000737:chemistry / Q000378:metabolism
chemical_list: D008744:Methylamines; C050107:cupredoxin; D001400:Azurin; D003300:Copper; C027451:methylamine; C021567:methylamine dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors