lipids

sphingomyelin (SP), gangliosides

phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS), phospatidylinositol (PI), cardiolipin (CL)

• phosphoglyceride
• sphingomyelin
• archaeal lipid

• 1. structure of LB is inherent in structure of constituent molecules
• 2. growth is rapid and spontaneous in aq sln

• 1. many non-covalent interactions
• 2. no edges w/ hydrocarbons next to water...compartmentalization is favored
• 3. self-sealing (hole unfavorable)

• 1. phobic-primary interaction; btw tails
• 2. VdW-btw tails; favors close packing
• 3. electrostatic-leads to H bonds btw polar heads and water

LB used for drug delivery; fuses directly w/ PM of target cell so contents are delivered directly and bypasses circulation and digestive system; not v selective unless target signals exploited

require detergent or organic solv to stabilize

interact w/ integral mem prot or w/ polar head groups of lipids

solubilized by mild cdns (high ionic strength)

i.e. bacteriorhodopsin

most common structural motif for mem spanning regions of prot; composed of phobic AA but has loops w/ philic AA that extend in cytoplasmic and exoplasmic aq env

i.e. bacterial porin

phobic AA on outside of pore (touching tails); philic AA line center of pore to make an aq env

ex of integral mem prot that does not span entire lipid bilayer; dimerization leads to formation of phobic channel in the mem

dimerization forms a phobic channel in the LB: prostaglandin's subst is arachadonic acid which is phobic; arachadonic acid does not have to leave the phobic env of the LB to find prostaglandin AS

arachadonic: generated by hydrolysis of lipids; why in BL mem to start w/

inhibits prostaglandin synthesis by transferring acetyl group to Ser 530 of prostaglandin channel; blocks subst access to AS

note: Ser is polar AA in polar channel of nonpolar BL

prot that are normally soluble are attached to peripheral mem prot through cov interaction

peripheral mem prot covalently attached to phobic groups through cysteine

peripheral mem prot covalently attached to phobic groups through cysteine

peripheral mem prot covalently attached to phobic groups through C terminus

facilitates lateral diffusion of prot

temp at which half of lipid mol are solid and half are fluid

proportional to mol diffusion coefficient and conc grad

rate ~ D x (C_side1/C_side2)

func of lipid solubility of mol; philic mol diffuse slowly and phobic mol diffuse rapidly

diff in conc across mem

• occurs from area of higher conc to area of lower conc
• the greater the conc diff, the greater the rate of diff

• use simple diffusion
• 1. sheds its solvation shell of water
• 2. dissolves in the hydrocarbon core of the mem
• 3. diffuses through core to other side of mem along conc grad
• 4. resolvated by water on other side

does not require E; aka facilitated diffusion

• l'esempio di facilitate diffusion and ligand gated channels
• transports Na and K ions along conc grad in response to neuronal signals

goes in opp direction as conc grad; requires E

• l'esempio di active transport
• exchanges Na and K against their conc grad using ATP hydrolysis; essential for synaptic transmission

voltage gated passive transport

ligand gated passive transport; allows Na and K down their grad once 2 Ach bind to receptor

cAMP regulated passive transport

passive transport

transporter passive transport

primary ATPase active transport

primary redox coupled active transport

ATP binding cassette active transport

secondary active transport

ATP hydrolysis moves mol against its conc grad

grad of mol X established by primary active transport; mvmt of X back into cell down its conc grad provides energy to drive co-transport of second mol, S, against its conc grad

transports a mol in one direction

cotransport of two mol in same direction

cotransport of 2 mol in opp directions

• G=RTln(C_side2/C_side1)
• G changes as a func of concentration ratio; linear relationship

G=RTln(Cside2/Cside1) + ZFV

• F=faraday
• V=potential in volts across mem
• Z=charge

G changes as a func of mem pot; linear relationship

uniporter; primary active transport

transports Ca against its conc grad using E of ATP hydrolysis; against conc grad bc going into sER where there is already buttloads of Ca

basolateral side of epithelial cells, symporter; secondary active transport (mvmt allowed by Na/K ATPase)

transports gluc against its conc grad using downhill flow of Na along its conc grad (from grad set up by Na/K pump)

uniporter; passive transport; voltage gated ion channel

once pore becomes too small, K must shed its outer layer of water in order to fit through

achieved by AA in pore-K can interact w/ TVGYG w/in 3 angstrom diameter pore (other ions are too small or too large to fit through)

inactivation domain-positively charged ball (tethered by chain domain to channel)

• closed state: bal is located in cytosol (not yet depolarized from AP)
• open state: depolarization from AP opens channel and allows for neg binding site for pos ball
• inactive state: pos ball moves into neg binding site and blocks channel

• drugs that can be used to disrupt ionic grad in microorganisms
• surround ions and shuttle them across mem

cmpds that collapse ionic grad (w/o ionic grad...no APs and no transport of anything)

sm, cyclic ionophore that disrupts K gradients by binding K and carrying it across mem

ionophore that disrupts Na gradients