The functional biology of membrane biochemistry over the tree of life Flashcards
main types of membrane chemistry
bacterial and archaeal
bacterial membrane chemistry
isoprenoid, ether, G1P (right handed)
bacterial membrane chemistry
fatty acid, ester, G3P (left handed)
what membrane chemistry do eukaryotes have?
bacterial type
why is it hard to get membrane chemistry from genomic data?
the pathways are mostly the same and a lot of flipping can occur, makes it hard to figure out- we also don’t know all the steps
example of within-group lipid diversity
differences in tail-linked phospholipids, e.g.. caldarchcaeol may strengthen membranes, good for extremophiles
current hypothesis for membrane changes
transition around LUCA, then a secondary transition in eukaryotes to a more bacterial-like membrane?
how can we test which lipids may have been present in LECA?
trying to get bacteria to express archaeal type lipids to see if having both lipid types is possible- seemed quite difficult- maybe it wasn’t both at the same time?
feature of archaeal membranes which might be related to their biology
proton (and water and urea and glycerol) permeability is low- good for extreme environments, not leaking protons to increase efficiency
issues with the membrane permeability work
-measured at ecologically unrealistic concentrations
-looked at transfer out of liposomes only
-liposomes also aren’t shaped like actual cells- they’re tinyyy
-not many metabolites
what did an experiment looking at big vesicles and how solutes move in find?
archaeal membranes seem more permeable to substrates- amino acids, sugars, nucleobases
transporter distribution across membrane types
archaea seem to have reduced repertoires of transporters compared to bacteria- this must have also shifted with membrane type in eukaryotes
