AMINO-ACID-SEQUENCE OF THE SMALL CADMIUM-BINDING PROTEIN (MP-II) FROMNEREIS-DIVERSICOLOR (ANNELIDA, POLYCHAETA) - EVIDENCE FOR A MYOHEMERYTHRIN STRUCTURE

The primary sequence of the low-molecular-mass cadmium-binding protein metalloprotein II of Nereis diversicolor (Hediste diversicolor, recen t denomination) has been determined. This protein is composed of 119 a mino acids and has 80.8% identity with the N. diversicolor myohemeryth rin [Takagi, T. & Cox, J. A. (1991) FEBS Lett. 285, 25-27]. The fact t hat iron, which normally binds to myohemerythrin, is not found to be a ssociated with the cadmium-binding protein metalloprotein II in cadmiu m-exposed animals could be the result of the complete abolition of the iron-binding capacity of the protein due to the binding of cadmium.