alpha-Chain contacts in the polymerisation of sickle haemogloblin.

Five new double-mutant haemoglobins composed of betaS chains and alpha chains with different substitutions, which are located at the surface of the tetramer, have been prepared. Although all the hybrids are more soluble than deoxyhaemoglobin S, the individual differences between these molecules make it possible to evaluate several regions on the alpha chains for intermolecular contacts in the polymerisation of deoxyhaemoglobin S.