COOPERATIVE HOMODIMERIC HEMOGLOBIN FROM SCAPHARCA-INAEQUIVALVIS - CDNA CLONING AND EXPRESSION OF THE FULLY FUNCTIONAL PROTEIN IN ESCHERICHIA-COLI

The overexpression of the fully functional, cooperative homodimeric he moglobin of the bivalve mollusc, Scapharca inaequivalvis, has been acc omplished in E. coli from its cDNA. The latter was isolated by PCR amp lification of total RNA and sequenced. The cDNA-derived sequence diffe red by a single amino acid when compared to that previously obtained f rom purified protein. Interest in this hemoglobin resides in the uniqu e assemblage of the two identical subunits, with the heme groups facin g each other in the inside of the molecule, opposite to that occurring in vertebrate hemoglobins. The results presented here are the basis f or future studies of structure/function relationships by site directed mutagenesis.