Fluorescence studies of internal rotation in apohemoglobin alpha-chains.

The molecular dynamics of the apo alpha-chain of human hemoglobin have been examined using three different fluorescent probes, as well as by circular dichroism. All of these criteria are consistent with a significant loss of organized structure and molecular rigidity for the apo derivative. The apo alpha-chain thus contrasts with the apo beta-chain, which retains considerable rigidity and organized structure.