In most oxygenic phototrophs, including cyanobacteria, two independent enzymes catalyze the reduction of protochlorophyllide to chlorophyllide, which is the penultimate step in chlorophyll (Chl) biosynthesis. One is light-dependent NADPH:protochlorophyllide oxidoreductase (LPOR) and the second type is dark-operative protochlorophyllide oxidoreductase (DPOR). To clarify the roles of both enzymes, we assessed synthesis and accumulation of Chl-binding proteins in mutants of cyanobacterium Synechocystis PCC 6803 that either completely lack LPOR or possess low levels of the active enzyme due to its ectopic regulatable expression. The LPOR-less mutant grew photoautotrophically in moderate light and contained a maximum of 20 % of the wild-type (WT) Chl level. Both Photosystem II (PSII) and Photosystem I (PSI) were reduced to the same degree. Accumulation of PSII was mostly limited by the synthesis of antennae CP43 and especially CP47 as indicated by the accumulation of reaction center assembly complexes. The phenotype of the LPOR-less mutant was comparable to the strain lacking DPOR that also contained <25 % of the wild-type level of PSII and PSI when cultivated under light-activated heterotrophic growth conditions. However, in the latter case, we detected no reaction center assembly complexes, indicating that synthesis was almost completely inhibited for all Chl-proteins, including the D1 and D2 proteins.

• MeSH
• 2D gelová elektroforéza MeSH
• aktivace enzymů MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• buněčná membrána enzymologie   metabolismus   MeSH
• chlorofyl biosyntéza   genetika   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• fenotyp MeSH
• fotosystém I (proteinový komplex) genetika   metabolismus   MeSH
• fotosystém II (proteinový komplex) genetika   metabolismus   MeSH
• fototrofní procesy MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   metabolismus   MeSH
• protochlorofylid metabolismus   MeSH
• regulace genové exprese enzymů * MeSH
• regulace genové exprese u rostlin MeSH
• světlo MeSH
• Synechocystis enzymologie   genetika   metabolismus   účinky záření   MeSH
• transformace genetická MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• chlorofyl MeSH
• fotosystém I (proteinový komplex) MeSH
• fotosystém II (proteinový komplex) MeSH
• oxidoreduktasy působící na CH-CH vazby MeSH
• protochlorofylid MeSH
• protochlorophyllide reductase MeSH Prohlížeč