Structural and functional analysis of tomato sterol C22 desaturase

Abstract Background Sterols are structural and functional components of eukaryotic cell membranes. Plants produce a complex mixture sterols, among which β-sitosterol, stigmasterol, campesterol, cholesterol in some Solanaceae, the most abundant species. Many reports have shown that stigmasterol to β-sitosterol ratio changes during plant development response stresses, suggesting it may play role regulation these processes. In tomato ( Solanum lycopersicum ), correlate with induction only gene encoding sterol C22-desaturase (C22DES), enzyme specifically involved conversion stigmasterol. However, despite biological interest this enzyme, there is still lack knowledge about several relevant aspects related its structure function. Results study we report subcellular localization C22DES endoplasmic reticulum (ER) based on confocal fluorescence microscopy fractionation analyses. Modeling studies also revealed consists two well-differentiated domains: single N-terminal transmembrane-helix domain (TMH) anchored ER-membrane globular (or catalytic) oriented towards cytosol. Although TMH sufficient for targeting retention ER, interact be retained ER absence transmembrane domain. The observation truncated version lacking enzymatically inactive membrane essential activity. silico analysis region features could substrate recognition binding. Conclusions Overall, contributes expand current function unveil novel metabolism.