Term
| What are three types of noncovalent forces that drive protein folding? |
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Definition
| Ionic/electrostatic interactions, hydrogen bonds, hydrophobic interactions |
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Term
| What are two examples of ionic/electrostatic interactions? |
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Definition
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Term
| What are two noncovalent forces that must be overcome so that a protein can fold? |
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Definition
| enthalpic forces (ie: when unfolded polypeptide wants to bond with the solvent) and entropic forces |
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Term
| How are secondary structures stabilized? |
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Definition
| By hydrogen bonding between peptide amide (N-H) and carbonyl groups (C=O) |
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Term
| How many residues are in a typical helix? |
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Definition
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Term
| What does it mean when you way "Helices are often amphipathic" |
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Definition
| They have distinct hydrophobic and hydrophilic sides |
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Term
| What amino acid breaks alpha helices? |
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Definition
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Term
| What arrangement of the polypeptide chains in a beta-pleated sheet is the most stable? |
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Definition
| anti-parallel (parallel and mixed are less stable) |
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Term
| Where would you find a "turn" in a peptide chain? |
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Definition
| Usually at protein surfaces. They contain hydrophilic residues (ie: proline, glycine) |
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Term
| How could you have charged or hydrophilic residues in a generally hydrophobic protein core? |
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Definition
| They form complementary interactions (like salt bridges) |
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Term
| What is tertiary structure? |
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Definition
| The final arrangement of domains within the folded protein |
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Term
| What are the steps in protein folding? |
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Definition
| primary structure --> "molten globule complex" (exhibit secondary structures of alpha helices and beta sheets) --> tertiary structure --> quaternary structure |
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Term
| What are chaperones called "heat shock proteins?" |
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Definition
| They are induced during stress (eg: heat shock) |
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Term
| What does prolyl cic-trans isomerase do? |
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Definition
| Accelerates the rotation around the peptide bond of proline (which is typically very slow) |
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Term
| How does ubiquitin link to lysine? |
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Definition
| amide bonds with the Ub C-terminus |
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Term
| What enzyme series activates ubiquitin? |
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Definition
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Term
| What enzyme series activates ubiquitin? |
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Definition
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Term
| What happens when a protein is marked by a chain of at least 4 ubiquitin molecules? |
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Definition
| It is degraded by proteasomes |
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Term
| What are 5 examples of amyloid diseases? |
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Definition
| Alzheimer's, Parkinsons, PolyQ, Prion, Systemic amyloidosis |
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