title: Localization of Pcb antenna complexes in the photosynthetic prokaryote Prochlorothrix hollandica.
abstract: The freshwater filamentous green oxyphotobacterium Prochlorothrix hollandica is an unusual oxygenic photoautotrophic cyanobacterium differing from most of the others by the presence of light-harvesting Pcb antenna binding both chlorophylls a and b and by the absence of phycobilins. The pigment-protein complexes of P. hollandica SAG 10.89 (CCAP 1490/1) were isolated from dodecylmaltoside solubilized thylakoid membranes on sucrose density gradient and characterized by biochemical, spectroscopic and immunoblotting methods. The Pcb antennae production is suppressed by high light conditions (>200 mumol photons m(-2) s(-1)) in P. hollandica. PcbC protein was found either in higher oligomeric states or coupled to PS I (forming antenna rings around PS I). PcbA and PcbB are most probably only very loosely bound to photosystems; we assume that these pigment-protein complexes function as low light-induced mobile antennae. Further, we have detected alpha-carotene in substantial quantities in P. hollandica thylakoid membranes, indicating the presence of chloroplast-like carotenoid synthetic pathway which is not present in common cyanobacteria.
authors.affiliation: Institute of Plant Molecular Biology, Biology Centre, Academy of Sciences of the Czech Republic, Branisovská 31, 37005 Ceské Budejovice, Czech Republic.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Herbstová
authors.forename: Radek
authors.initials: R
authors.lastname: Litvín
authors.forename: Zdenko
authors.initials: Z
authors.lastname: Gardian
authors.forename: Josef
authors.initials: J
authors.lastname: Komenda
authors.forename: Frantisek
authors.initials: F
authors.lastname: Vácha
mesh_terms: D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D008027:Light; D010788:Photosynthesis / Q000502:physiology*; D045331:Photosystem I Protein Complex / Q000302:isolation & purification / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000302:isolation & purification / Q000378:metabolism; D048928:Prochlorophytes / Q000378:metabolism; D019692:Prochlorothrix / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex