Term
| What can cause distortions in transmembrane alpha helices and implications does this have on the protein? |
|
Definition
| Prolines kinks in the helix because it lacks the hydrogogen bond with back bone and it messes up ideal helix angles because of sterics. these kinks create weak points in helix that allow movements required for transmembrane transport. |
|
|
Term
| Despite proline kink? helix distortion are one way to ? what percentage of membrane distortions com from proline residues ? |
|
Definition
even distorted helices are highly stable . create structure diversity
60% |
|
|
Term
Amino acid preferred locations of charged residues, postive charged ?
What about special cases ? |
|
Definition
lipid water interface, cytoplasmic face (positive insde rule),
Tyrpophan histidine tyrosine ( mixed character) have both polar and aromatic hydrophobic parts |
|
|
Term
| Which amino acids have mixed character and what does this mean for there prefered locations in transmembrane helices |
|
Definition
| Tyrptophan, Histidine, Tyrosine. have polar and nonpolar aromatic parts. at lipid water interfaces |
|
|
Term
| Which amino acids are situated at the lipid water interface? |
|
Definition
charged Asp,Glu,Arg,Lys, His
Special cases - Trp, Try, His |
|
|
Term
| What is snorkeling? anitsnorkeling |
|
Definition
| when a sidechain of a lipid interface amino acid sidechain sticks out of the membrane . Antisnorkeling is the only sidechain is in the membrane |
|
|
Term
| Which residue typically participate in snorkeling? anitsnorkeling |
|
Definition
|
|
Term
| What is the advantage of making beta sheet membrane proteins |
|
Definition
| less genetic information neeeded per barrel 9-11 residues vs 21-25 residues |
|
|
Term
| Properties of Lipid anchored Membrane proteins? |
|
Definition
covalentl linked to membrane
can reversibly bind to proteins (transiet) |
|
|
Term
| Four types of lipid-anchored proteins |
|
Definition
Amide linked myristoyl anchors
Thioester-linked fatty acyl anchors
Thioether-linked prenyl anchors
Glycosyl phophatidylinositol anchors |
|
|
Term
| Properties of Amide linked myristoyl (where it binds both sides) and what residue it links to on polypetide |
|
Definition
alyways bound to myristic acid
linked at N-terminal
Glycine |
|
|
Term
| Thioester-linked and acy anchors , what lipids does it bind too, which aminio acids does it bind too? |
|
Definition
myristate, palmitate, stearate, oleate
Cys , Ser, Thr |
|
|
