title: Extracellular carbonic anhydrases of the stromatolite-forming cyanobacterium Microcoleus chthonoplastes.
abstract: Active extracellular carbonic anhydrases (CAs) were found in the alkaliphilic stromatolite-forming cyanobacterium Microcoleus chthonoplastes. Enzyme activity was detected in intact cells and in the cell envelope fraction. Western blot analysis of polypeptides from the cell envelope suggested the presence of at least two polypeptides cross-reacting with antibodies against both alpha and beta classes of CA. Immunocytochemical analysis revealed putative alpha-CA localized in the glycocalyx. This alpha-CA has a molecular mass of about 34 kDa and a pI of 3.5. External CAs showed two peaks of activity at around pH 10 and 7.5. The possible involvement of extracellular CAs of M. chthonoplastes in photosynthetic assimilation of inorganic carbon and its relationship to CaCO(3) deposition during mineralization of cyanobacterial cells are discussed.
authors: Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276 Russia.
authors: Elena
authors: E
authors: Kupriyanova
authors: Department of Biology, Universidad Autonoma de Madrid, 28049 Madrid.|Umeå Plant Science Centre, Department of Plant Physiology, University of Umeå, S-901 87 Umeå, Sweden.
authors: Arsenio
authors: A
authors: Villarejo
authors: Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276 Russia.
authors: Alexandra
authors: A
authors: Markelova
authors: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-Letiya Oktyabrya 7/2, Moscow, 117312 Russia.
authors: Lyudmila
authors: L
authors: Gerasimenko
authors: Institute of Microbiology, Russian Academy of Sciences, Prospect 60-Letiya Oktyabrya 7/2, Moscow, 117312 Russia.
authors: Georgy
authors: G
authors: Zavarzin
authors: Umeå Plant Science Centre, Department of Plant Physiology, University of Umeå, S-901 87 Umeå, Sweden.
authors: Göran
authors: G
authors: Samuelsson
authors: Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276 Russia.
authors: Dmitry A
authors: DA
authors: Los
authors: Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow, 127276 Russia.
authors: Natalia
authors: N
authors: Pronina
mesh_terms: D015153:Blotting, Western; D002119:Calcium Carbonate / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000378:metabolism*; D000458:Cyanobacteria / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D015180:Electrophoresis, Gel, Two-Dimensional; D019276:Glycocalyx / Q000737:chemistry
chemical_list: D002256:Carbonic Anhydrases; D002119:Calcium Carbonate