Term
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Definition
In all eukaryotic membranes
Structurally more rigid than phospholipids
Makes membranes a little less fluid
Decreases permeability of membrane to small water-soluble molecules
Prevents hydrocarbon chains from coming together and crystallizing |
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Term
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Definition
| The structure of cholestorol |
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Term
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Definition
| Unsaturated v. Saturated hydrocarbon chains |
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Term
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Definition
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Term
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Definition
– more saturated
More Sphingolipids and cholesterol
Longer and straighter lipid tails |
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Term
| Structure/ function of lipid rafts |
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Definition
Signaling platforms in cells
Certain proteins that are involved in transducing signals localize to these domains |
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Term
Biochemically, these domains can be distinguished from the rest of the ______
Remove cholesterol with___________This disturbs structure of lipid rafts
Result is lose ________ |
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Definition
| Plasma membrane, B-methylcyclodextrin, signal transduction of some receptors |
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Term
| Asymmetry of phospholipids in membranes |
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Definition
Choline containing phospholipids - outer leaflet
PS and PE inner leaflet
Flip-flop - occurs when membrane is made or when cell is distressed (apoptosis) |
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Term
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Definition
| minor very important phospholipid for signaling |
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Term
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Definition
| - always on non-cytosolic side of membrane (due to how they are made – you will understand this later) |
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Term
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Definition
integral membrane proteins (it is IN the membrane)
Amphipathic
Modifications |
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Term
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Definition
-helix - transmembrane segment of protein often this structure
b-sheets also can be integral membrane structures
Single-pass and multi-pass proteins |
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Term
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Definition
forms a pore or channel
polar amino acid side-chains face the inside of aqueous channel
hydrophobic non-polar amino acid side-chains face outward and interact with lipid bilayer |
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Term
| Peripheral membrane protein |
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Definition
Don’t interact with lipid part of membrane (not IN membrane)
Bound by non-covalent interactions |
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Term
| Predicting protein structure - |
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Definition
due to the amino acids in the protein - called a hydropathy plot
Freeze-fracture
Liposome generation
Detergent solubilization |
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Term
Hydropothy Plot
Look at regions of the protein amino acid structure for stretches of _____ amino acids at a time – if ______, these may be regions that are ____________
Predict function of proteins based on _______ |
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Definition
| 10-20, hydrophobic, membrane domains of integral membrane proteins, structure. |
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Term
Hydropathy -
positive number-
is protected from the |
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Definition
how much energy is required to solubilize a segment of protein in water.
means that a lot of energy is required because that segment of the protein
hydrophilic properties of water whereas negative number is highly soluble in water) |
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Term
| Freeze fracture technique |
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Definition
Freeze cells in liquid nitrogen
Break the ice - fracture plane between bilayer. You will see transmembrane protein. |
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Term
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Definition
| E exposed face and P exposed face, freeze. |
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Term
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Definition
| P face appears up, and E face is downward. |
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Term
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Definition
| hypotonic Lysis, wash ---> leaky ghost, wash and reseal--> sealed ghost, Distrupt and reseal--> right side out vesticles, inside out vesticles. |
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Term
| Studying sidedness of transmembrane proteins |
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Definition
Radioactively or fluorescently label in RBC ghosts
Enzymatic degradation
Crosslinking (peripheral membrane proteins) |
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Term
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Definition
Make synthetic lipid bilayers or liposomes
Insert purified proteins
Major limitation - size of the protein visible |
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Term
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Definition
| are amphipathic molecules that disrupt membranes |
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Term
| Ionic (charged) detergent - |
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Definition
| SDS - very harsh and will disrupt all membranes |
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Term
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Definition
| Triton X-100 - more gentle detergent and can be used to solubilize particular compartments |
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Term
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Definition
Can separate proteins from lipids for analysis
Can analyze the isolated proteins in a more controlled environment (cells are very complex!) |
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Term
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Definition
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Term
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Definition
Isolate a protein and then place it into an artificial membrane (liposome)
Look for protein localization, function, interactions with other proteins etc |
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Term
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Definition
| Detergents after isolating a protein. |
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Term
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Definition
SDS coats proteins with detergent (neg charged)
Proteins migrate through gel to negative electrode (run to red)
Separation based on size and sometimes on shape
Molecular weight |
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Definition
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