FIG. 2.

SDS-PAGE analysis of the in vitro-synthesized cyanophycin-like polymers. (a) Reactions catalyzed by the cyanophycin synthetase-containing soluble cell fraction (0.5 mg of protein ml⁻¹) and by the purified cyanophycin synthetase (0.04 mg of protein ml⁻¹) at 30°C overnight in the presence of different primers at a concentration of 1 mg ml⁻¹ as described in Materials and Methods. Lane 1, soluble cell fraction with cyanophycin purified from Synechococcus sp. strain MA19; lane 2, soluble cell fraction with chemosynthetic poly-α,β-dl-aspartic acid; lane 3, soluble cell fraction with N-acetylglucosamine; lane 4, soluble cell fraction with α-arginyl aspartic acid dipeptide (lot 197FO334); lane 5, cyanophycin purified from Synechococcus sp. strain MA19; lane 6, purified cyanophycin synthetase with the α-arginyl aspartic acid dipeptide (lot 197FO334); lane 7, purified cyanophycin synthetase; lane 8, soluble cell fraction. (b) Lane 1, cyanophycin purified from E. coli (cphA_MA19co). The sizes of molecular mass standard proteins (lane Std) are indicated on the left.