Circular Dichroism Spectra of Native 37 S Hemocyanin from the Spider Eurypelma Californicum and Its Subunits

Abstract

The 37 S hemocyanin of the tarantula Eurypelma californicum has a molecular mass of 1.8 × 10⁶ Da and is built up from 24 subunits. Under alkaline conditions the molecule disaggregates into the monomers a, d, e, f, g and the dimers bc and ff (1). By reassembly experiments it was shown, that all seven subunits are necessary to reconstitute the native 37 S hemocyanin (2). Each subunit seems to play a specific role in the assembly of the whole molecule, and may therefore play an individual role in “molecular physiology” (i. e. Bohr effect and cooperativity). The heterogeneity of the immunologically distinct subunits seems to be based only on different amino acid sequences and not on post-translational modifications (1, 3).