Protein Structure and Folding

Vocabulary flashcards about protein structure and folding.

Proline

Most conformationally restricted amino acid in a protein.

Glycine

Least conformationally restricted amino acid in a protein.

Hydrogen Bond (α helix)

Stabilizes the α helix through hydrogen bonds between the carbonyl oxygen of the nth amino acid residue and the -NH group of the (n + 4)th amino acid residue.

Proline

Amino acid typically not found in the α helix.

Parallel and Antiparallel

Describes the arrangement of peptide strands in beta-sheets.

Glycine

Collagen requires this every third amino acid for triplet helix formation.

Scurvy

Condition resulting from the inability of prolyl oxidase to oxidize proline residues in collagen to hydroxyproline in the absence of ascorbic acid.

Glutamate and Lysine

Amino acids whose side chains have groups with the greatest ability to stabilize the tertiary structure of a protein.

Protein Denaturation

Effect of the low pH found in the gut on dietary protein.

Aggregation of Hydrophobic Regions

Occurs first when folding a disordered polypeptide chain into a stable protein formation.

Protein Denaturation

Effect of high concentration of a chaotropic agent on a protein.

Molecular Chaperone Proteins

Function by preventing premature folding by binding hydrophobic regions of the protein.

High Peak Overlap

Why conventional one dimensional NMR spectroscopy is not generally an effective tool for determination of protein structure.

Hydrophobic Effect, Salt Bridges, Electrostatic Interactions, Hydrogen Bonding

Forces that stabilize protein structure.

Refolding of Reduced and Denatured RNase A

Demonstrates that 1° structure can determine 3° structure.

ATP Hydrolysis

Chaperonins such as the GroEL/ES system require this.

Protein Diseases

Diseases caused by mutations affecting the 1° or 3° structure or changes in the post-synthetic processing of proteins.

Alpha helix and Beta sheet

Hydrogen bonds and maximum separation of amino acid side chains make this very stable and energetically favorable.

Chaperonin

Helps fold some proteins in their lowest energy state.

Creutzfeld-Jakob Disease

Disease caused by the aggregation of a misfolded protein.

pH, Temperature, Ionic Strength

Proteins can denature due to a change in these conditions.

Denature and Likely Precipitate

Proteins with hydrophilic groups on the exterior would do this during a protein purification with a change from water to an organic solvent.

Spontaneous refolding of proteins into their native state under physiologic conditions.

Observation about protein refolding that helped solidify the connection between primary amino acid sequence and 3-D structure.

Improper aggregation of hydrophobic segments

Molecular chaperones bind to unfolded or partially folded polypeptide chains to ensure that this does not occur.