Abstract
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.