title: Structural modeling and environmental regulation of arginine decarboxylase in Synechocystis sp. PCC 6803.
abstract: Arginine decarboxylase (ADC) is the first enzyme in the alternative route to putrescine in the polyamine biosynthesis pathway in bacteria and plants. In this study, we have focused on the effects of various types of short-term stresses on the transcript amount and specific activity of Synechocystis sp. PCC 6803 ADC. Our results reveal that the steady-state transcript accumulation and enzyme activity are not connected in a simple manner, since only photoheterotrophy and synergistic salt and high-light stress affected both parameters similarly. Changes in the steady-state ADC mRNA accumulation under the other short-term stress conditions studied had only a small impact on enzyme activity, suggesting post-translational regulation. Based on structural modeling, Synechocystis ADCs have a putative extra domain, which might be involved in the post-translational regulation of ADC activity in Synechocystis. In addition, two symmetric inter-subunit disulfide bonds seem to stabilize the dimeric structure of ADCs. There are two genes coding for ADC and agmatinase, another polyamine pathway enzyme, in Synechocystis genome, while the genes coding for ornithine decarboxylase and for some other enzymes in the polyamine pathway were not identified with homology searches.
authors.affiliation: Department of Biology, Laboratory of Plant Physiology and Molecular Biology, University of Turku, 20014, Turku, Finland.
authors.forename: Saowarath
authors.initials: S
authors.lastname: Jantaro
authors.forename: Heidi
authors.initials: H
authors.lastname: Kidron
authors.forename: Delphine
authors.initials: D
authors.lastname: Chesnel
authors.forename: Aran
authors.initials: A
authors.lastname: Incharoensakdi
authors.forename: Paula
authors.initials: P
authors.lastname: Mulo
authors.forename: Tiina
authors.initials: T
authors.lastname: Salminen
authors.forename: Pirkko
authors.initials: P
authors.lastname: Mäenpää
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002262:Carboxy-Lyases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011073:Polyamines / Q000378:metabolism; D016415:Sequence Alignment; D046939:Synechocystis / Q000201:enzymology* / Q000235:genetics
chemical_list: D011073:Polyamines; D002262:Carboxy-Lyases; C019722:arginine decarboxylase