Structure of Helix pomatia oxy-beta-hemocyanin and deoxy-beta-hemocyanin tubular polymers

Mild trypsinolysis of Helix pomatia beta-hemocyanin leads to the formation of tubular polymers after removal of the collar part [van Breemen, J.F.L., Wichertjes, T., Muller, M.F.J., van Driel, R., and van Bruggen, E.F.J. (1975) Eur. J. Biochem. 60, 129--135]. Three-dimensional image reconstruction from electron micrographs of negatively stained tubular polymers showed: (a) alternating deep and shallow grooves in between the 10 helical chains, (b) the presence and position of two domains within each morphological wall-unit of the Mellema and Klug model [Mellema, J. E. and Klug, A. (1972) Nature (Lond.) 239, 146--150]. Optical diffraction of oxy and deoxygenated tubular polymers indicate a significant decrease in diameter with a concomitant increase in length upon deoxygenation.