Membrane integration and intracellular localization of microsomal cytochrome P450

点击翻译按钮获取中文摘要

Using cytochrome P450 molecule as a typical model of endoplasmic reticulum membrane protein, we investigated its biosynthesis, integration into membrane, and localization in endoplasmic reticulum, and have demonstrated the follows :(1) Type I signal-anchor sequence (SA-I) which is essential for correct folding of P450 molecule shows a key role of topogenic sequence during membrane integration of multispanning membrane proteins.(2) For membrane integration of SA-I, a amino acid resides which induce turn structure are essential, when the amino-terminal domain is tend to form tight secondary structure.(3)The length of hydrophobic segment of SA-I is one of the key determinants of intracellular location of ER.(4) SA-I is integrated into the membrane just after the hydrophobic segment emerges from ribosomes.(5) NADPH-cytochrome P450 reductase also possesses SA-I as P450 molecule does.