The statistical block copolymer structure of K, I, and K2. K and I from K. alvazerii and E. denticulatum contain 3 to 11 mol% of G4S-DA2S and G4S-DA, respectively [10,60,62]. The sketches in the top row of the figure illustrates the block copolymer nature of K2 in the absence of salt (coil conformer), which includes sequences of G4S-DA2S (red sphere) and G4S-DA (blue sphere) interrupted by a more sulfated G4S-D2S,6S or G4S-D6S (green sphere), respectively. With the addition of salt, each block can adopt a helical conformation [54,55]. With more salt, full helices are formed with different levels of flexibility depending on the K or I block [67,68].