PROSITE documentation PDOC00639

Oleosins signature

Oleosins [1] are the proteinaceous components of plants' lipid storage bodies called oil bodies. Oil bodies are small droplets (0.2 to 1.5 mu-m in diameter) containing mostly triacylglycerol that are surrounded by a phospholipid/ oleosin annulus. Oleosins may have a structural role in stabilizing the lipid body during dessication of the seed, by preventing coalescence of the oil. They may also provide recognition signals for specific lipase anchorage in lipolysis during seedling growth. Oleosins are found in the monolayer lipid/ water interface of oil bodies and probably interact with both the lipid and phospholipid moieties.

Oleosins are proteins of 16 Kd to 24 Kd and are composed of three domains: an N-terminal hydrophilic region of variable length (from 30 to 60 residues); a central hydrophobic domain of about 70 residues and a C-terminal amphipathic region of variable length (from 60 to 100 residues). The central hydrophobic domain is proposed to be made up of β-strand structure and to interact with the lipids [2]. It is the only domain whose sequence is conserved and we have therefore selected a section from that domain as a signature pattern.