Figure 2.

The sequence properties of P450MT2. (A) 3–6 μg of P450MT2 and 1A1 proteins were resolved as described in Fig. 1 and transferred to PVDF membranes. Bands corresponding to P450MT2b and 1A1 were excised and subjected to proteolytic digestion and HPLC analysis. The absorbency profiles at 260 nm are presented. (B) The microsomal P4501A1 and mitochondrial P450MT2a and MT2b protein bands were transblotted to PVDF membrane and sequenced by Edman degradation as described in Materials and Methods. The nature of 1A1Mut and +33/Mut cDNA constructs carrying R34D and K39I substitutions, as well as NH₂-terminal deletion clones are indicated. (C) The chimeric signal properties of P4501A1 are indicated. The NH₂-terminal-most luminal region is indicated in dark, and the transmembrane region is indicated in gray. The sequence 33–44 of the protein containing three basic amino acid residues at positions 34, 39, and 42 is predicted to function as a putative mitochondrial-targeting sequence.