Amino Acid Sequence of the a-Chain of the Tetrameric Haemoglobin of the Bivalve Mollusc Anadara Trapezia

Abstract

The amino acid sequence of the IX-chain of the tetrameric haemoglobin of the bivalve mollusc A. trapezia shows 153 amino acid residues, longer than invertebrate globins previously sequenced. The amino terminal residue is acetylated as shown by nuclear magnetic resonance and mass spectrographic analysis of an N-terminal peptide. There are additional residues at the amino terminus, similar to the IX-globin of the shark and lamprey globin. In common with other invertebrate globin sequences, when compared with vertebrate globins it is necessary to insert extra gaps in interhelical regions of the vertebrate alignment to preserve homology.