Stabilization of phycocyanins and photosystems by small heat shock protein in cyanobacteria under oxidative stress

Abstract

Members of small heat shock protein (sHsp) family range in monomer size from 12−43 kDa, are characterized by a conserved alpha-crystallin domain. In order to elucidate the role of sHsp under oxidative stress generated by methylviologen or hydrogen peroxide, we analyzed phenotype of a cyanobacterial mutant which constitutively expresses sHsp or whose gene encoding sHsp is disrupted. Small Hsp stabilized phycocyanin and photosystem complexes in the cyanobacteria Synechococcus sp.PCC 7942 and Synechocystis sp. PCC 6803.