Localization of Pcb antenna complexes in the photosynthetic prokaryote Prochlorothrix hollandica.
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.
Herbstová
Miroslava
M
Institute of Plant Molecular Biology, Biology Centre, Academy of Sciences of the Czech Republic, Branisovská 31, 37005 Ceské Budejovice, Czech Republic.
Litvín
Radek
R
Gardian
Zdenko
Z
Komenda
Josef
J
Vácha
Frantisek
F
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
D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex