Abstract
Long-chain polyunsaturated fatty acids (PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid, are essential fatty acids for human, which provide various favorable effects on health, including anti-inflammatory and anti-tumor effects. PUFA-containing phospholipids change the physicochemical properties of biological membranes and might modulate the function of membrane proteins. However, it is not fully understood how PUFA exerts their function. EPA and DHA are found in various bacteria isolated from cold environments, such as Polar Regions and deep sea, and are synthesized as an acyl chain of their membrane phospholipids. By using these bacteria, which have much simpler cell structure than eukaryotes, it was demonstrated that PUFA plays novel physiological roles in their environmental adaptation. Here, we describe the biosynthesis mechanism of EPA and its physiological role in cold adaptation of a bacterium isolated from Antarctic seawater. We propose that EPAcontaining phospholipids support the function of membrane proteins involved in cell division and membrane transport at low temperatures as a hydrophobic chemical chaperone.
