Cell walls of the unicellular cyanobacterium Synechocystis sp. PCC 6714, isolated from cell homogenates, were found to be unusually resistant against extraction with various detergents, organic solvents, chaotropic agents, and proteases. The major outer membrane proteins (Mr 67,000; 61,000; 94,000) were solubilized by differential SDS-extraction and purified by prepara tive SDS-PAGE. The extra...