Which component of membranes helps maintain fluidity at lower temperatures?
Preservation of fluidity when temperature drops relies on lipid composition adjustments preventing gel formation that would freeze transporters. Cholesterol with rigid tetracyclic nucleus and three beta hydroxyl inserts among phospholipids orientation hydroxyl near carbonyl oxygen aligning ring parallel to upper acyl chains. At low temperatures it sterically hinders all trans chain crystallization by creating free volume and disrupting van der Waals lattice lowering order parameter measured by DPH anisotropy from zero point eight to zero point four. At high temperatures same rigid ring dampens
Ref: Mourtsen & Zuckermann, FEBS Letters 2004, Cholesterol broadens transition maintains fluidity.
