Elucidating the site of action of oxalate in photosynthetic electron transport chain in spinach thylakoid membranes.
The effects of oxalate on PS II and PS I photochemistry were studied. The results suggested that in chloride-deficient thylakoid membranes, oxalate inhibited activity of PS II as well as PS I. To our knowledge, this is the only anion so far known which inhibits both the photosystems. Measurements of fluorescence induction kinetics, YZ* decay, and S2 state multiline EPR signal suggested that oxalate inhibited PS II at the donor side most likely on the oxygen evolving complex. Measurements of re-reduction of P700+ signal in isolated PS I particles in oxalate-treated samples suggested a binding site of oxalate on the donor, as well as the acceptor side of PS I.
School of Life Sciences, Devi Ahilya University, Vigyan Bhavan, Khandwa Road, Indore 452017, M.P., India. anjanajajoo@hotmail.com
Anjana
A
Jajoo
Archna
A
Sahay
Pooja
P
Singh
Sonal
S
Mathur
Sergei K
SK
Zharmukhamedov
Vyacheslav V
VV
Klimov
Suleyman I
SI
Allakhverdiev
Sudhakar
S
Bharti
D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport / Q000187:drug effects; D007700:Kinetics; D010070:Oxalates / Q000494:pharmacology*; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018724:Spinacia oleracea / Q000187:drug effects* / Q000378:metabolism*; D013696:Temperature; D020524:Thylakoids / Q000187:drug effects* / Q000378:metabolism*
D010070:Oxalates; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex