Gene synthesis aids study of cytochrome

Abstract

In an effort to better understand characteristics of the heme protein cytochrome b 5 , including how amino acid side chains determine the properties of the heme iron, researchers have synthesized the gene that encodes the protein and have expressed it in bacteria. A number of features make cytochrome b 5 an ideal target for site-directed mutagenesis experiments, says Stephen G. Sligar, biochemistry professor at the University of Illinois, Urbana. It plays an important role in electron transfer reactions, including reduction of cytochrome P-450 in the liver and regeneration of ferrous hemoglobin in red blood cells. The protein's amino acid sequence is highly conserved among species, and a high-resolution crystal structure has been determined for bovine cytochrome b 5 . The problem, however, is that efforts to express native mammalian cytochromes at high levels in a bacterial system have not been successful. Why they have not been isn't entirely clear, Sligar says. To circumvent this problem and developed ...