The Prx6 subfamily takes its name from the first Prx to be crystallized, human PrxVI (Choi et al. 1998), formerly referred to as “ORF6”. Members of this subfamily include the bacterial Prx6 proteins, the 1-Cys plant Prxs from Arabidopsis thaliana and barley, the yeast mitochondrial Prx1 protein, and human PrxVI. Prx6 proteins are most similar to the AhpC/Prx1 subfamily, containing a C-terminal extension and forming B-type dimers and, in some cases, higher oligomeric states (Hall et. al 2010). However, in contrast to the AhpC-Prx1 subfamily, Prx6 subfamily members are predominantly 1-Cys, though 2-Cys representitives exist (Deponte and Becker 2005), and the direct reductant of Prx6 subfamily members is generally not known. Trx is able to reduce Saccharomyces cerevisiae Ahp1p (Pedrajas et al. 2000) but not human PrxVI (Kang et al. 1998). Other potential reductants include GSTπ (Manevich et al. 2004), glutaredoxin (Pedrajas et al. 2010), and ascorbate (Monteiro et al. 2007).
Aligned active site signatures (from DASP; Nelson et al. 2011) from the Prx6 subfamily (upper group) and one representative each of the other five subfamilies (lower group). Key residues of the active site signatures are noted by asterisks along the top. Shown below is the unrooted tree generated by Phylip’s Drawtree using the SDSC Biology Workbench tools.
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Pedrajas, J. R., Padilla, C. A., McDonagh, B., & Bárcena, J. A. (2010). Glutaredoxin participates in the reduction of peroxides by the mitochondrial 1-CYS peroxiredoxin in Saccharomyces cerevisiae. Antioxidants & Redox Signaling, 13(3), 249-258. PMID: 20059400