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pkn22 ( alr2502 ) encoding a putative Ser/Thr kinase in the cyanobacterium Anabaena sp. PCC 7120 is induced by both iron starvation and oxidative stress and regulates the expression of isiA
Author(s) -
Xu Wen-Liang,
Jeanjean Robert,
Liu Yong-Ding,
Zhang Cheng-Cai
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01019-6
Subject(s) - mutant , anabaena , biology , oxidative stress , biochemistry , gene , cyanobacteria , microbiology and biotechnology , oxidative phosphorylation , bacteria , genetics
In cyanobacteria, the isiA gene is required for cell adaptation to oxidative damage caused by the absence of iron. We show here that a putative Ser/Thr kinase gene, pkn22 ( alr2052 ), is activated by iron deficiency and oxidative damage in Anabaena sp. PCC 7120. A pkn22 insertion mutant is unable to grow when iron is limiting. pkn22 regulates the expression of isiA (encoding CP43′), but not of isiB (encoding flavodoxin) and psbC (CP43). Fluorescence measurement at 77 K reveals the absence of the typical signature of CP43′ associated with photosystem I in the mutant under iron‐limiting conditions. We propose that Pkn22 is required for the function of isiA/CP43′ and constitutes a regulatory element necessary for stress response.