Abstract
The characteristic 450 nm spectrum of cytochrome P450 is highly sensitive to denaturation of the protein structure. It is a sensitive indicator of the native conformation of the heme-containing catalytic domain of P450 molecules, and can be conveniently utilized in studying the mechanism of folding of P450 proteins in the cell. Microsomal forms of cytochrome P450 have a short proline-rich sequence following the N-terminal signal-anchor sequence. Similar proline-rich sequence is also found in the N-terminal region of the mature forms of mitochondrial P450s and some soluble bacterial P450s. The proline-rich sequence has been shown to be important for efficient folding of newly synthesized P450 proteins in Escherichia coli cells as well as in eukaryotic cells. The mechanism of participation of the proline-rich sequence in the folding of newly synthesized P450 peptides is not yet clarified.
