Conformational changes of a mitochondrial precursor protein on binding to phospholipid vesicles and SDS micelles. A circular dichroism and fluorescence spectroscopy study.

Conformations of an artificial mitochondrial precursor protein pCox IV-DHFR have been analyzed by CD and fluorescence spectroscopy in the presence of (cardiolipin-rich) phospholipid vesicles or SDS micelles. Binding of pCox IV-DHFR to phospholipid vesicles involves a conformational change, which is presequence-dependent, accompanies alteration in the secondary structure of the DHFR moiety, but is different from total unfolding of the polypeptide chain. On the other hand, a conformational change of the fusion protein on binding to the micelles of a positively charged detergent, SDS, is not presequence-dependent.