Functional characterisation of the peroxiredoxin gene family members of Synechococcus elongatus PCC 7942.
The genome of Synechococcus elongatus PCC 7942 encodes six peroxiredoxins (Prx). Single genes are present each for a 1-Cys Prx and a 2-Cys Prx, while four genes code for PrxQ-like proteins (prxQ-A1, -A2, -A3 and B). Their transcript accumulation varies with growth conditions in a gene-specific manner (Stork et al. in J Exp Bot 56:3193-3206, 2005). To address their functional properties, members of the prx gene family were produced as recombinant proteins and analysed for their peroxide detoxification capacity and quaternary structure by size exclusion chromatography. Independent of the reduction state, the 2-Cys Prx separated as oligomer, the 1-Cys Prx as dimer and the PrxQ-A1 as monomer. PrxQ-A2 was inactive in our assays, 1-Cys Prx activity was unaffected by addition of TrxA, while all others were stimulated to a variable extent by addition of E. coli thioredoxin. Sensitivity towards cumene hydroperoxide treatment of E. coli BL21 cells expressing the cyanobacterial PrxQ-A1 to A3 proteins was greatly reduced, while expression of the other Prx had no effect. The study shows differentiation of Prx functions in S. elongatus PCC 7942 which is discussed in relation to potential roles in site- and stress-specific defence.
Stork
Tina
T
Biochemistry and Physiology of Plants, Faculty of Biology, W5-134, Bielefeld University, 33501, Bielefeld, Germany.
Laxa
Miriam
M
Dietz
Marina S
MS
Dietz
Karl-Josef
KJ
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family; D010545:Peroxides / Q000378:metabolism; D054464:Peroxiredoxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016415:Sequence Alignment; D046940:Synechococcus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
D001426:Bacterial Proteins; D010545:Peroxides; D054464:Peroxiredoxins