Structure of hemocyanin II from the horseshoe crab, Limulus polyphemus. Sequences of the overlapping peptides, ordering the CNBr fragments, and the complete amino acid sequence.

The amino acid sequence of the largest fragment, CNBr Ia (203 residues) has been reported (Yokota, E., and Riggs, A. F. (1984) J. Biol. Chem. 259, 4739-4749). The amino acid sequences of the second largest fragment, CNBr Ib (142 residues), and of the 12 smaller fragments are reported in accompanying papers (Moore, M. D., Behrens, P. Q., and Riggs, A. F. (1986) J. Biol. Chem. 261, 10511-10519; Behrens, P. Q., Nakashima, H., and Riggs, A. F. (1986) J. Biol. Chem. 261, 10520-10525). The complete amino acid sequence of hemocyanin component II has been established by isolation and analysis of 13 methionine-containing peptides from either a tryptic digest or a Staphylococcus aureus strain V8 protease digest of whole carboxamidomethylated hemocyanin II. Hemocyanin II is composed of 628 residues and has a molecular weight with two copper atoms of 72,946.