Week 26 / Protein Structure Flashcards
Q: What are the two main types of secondary structure in fibrous proteins and small peptides revealed by X-ray structures?
A: The two main types of secondary structure are the α-helix and the β-sheet.
Q: How are α-helices and β-sheets formed in fibrous proteins and small peptides?
A: They are formed by hydrogen bonds between peptides.
Q: What type of secondary structure does α-keratin (hair) have?
A: α-keratin (hair) has an α-helix.
Q: What is the orientation of all protein α-helices?
A: All protein α-helices are right-handed.
Q: What type of secondary structure does β-keratin (silk) contain?
A: β-keratin (silk) contains β-sheets.
Q: What are the two main varieties of β-sheets?
A: The two main varieties of β-sheets are parallel and antiparallel β-sheets.
Q: What are other common secondary structures besides α-helix and β-sheet?
A: Other common secondary structures include β-barrel and twisted β-sheet.
Q: What is the tertiary structure of a protein?
A: The tertiary structure is the packing of secondary structures.
Q: How is the tertiary structure of myoglobin formed?
A: Myoglobin contains several different α-helices packed together to give a dense globular morphology.
Q: What types of interactions are commonly used in protein tertiary structure?
A: Common interactions include van der Waals, hydrophobic, electrostatic, and hydrogen bonds.
Q: What is the quaternary structure of a protein?
A: The quaternary structure involves multiple strands of amino acids.
Q: What is hemoglobin made up of?
A: Hemoglobin is made up of 4 separate myoglobin-like strands.
Q: What does each strand in hemoglobin contain?
A: Each strand contains a heme unit used to transport oxygen.
Q: How are the strands in hemoglobin held together?
A: The strands are held together by non-covalent forces.
Q: What is an α/β parallel β-sheet?
A: An α/β parallel β-sheet is a structure where α-helices and parallel β-sheets are interspersed within the protein, often forming a mixed secondary structure.
Q: What is an α+β antiparallel β-sheet?
A: An α+β antiparallel β-sheet is a structure where α-helices and antiparallel β-sheets are combined within the protein, typically forming a stable and organized secondary structure.
Q: Can many proteins regain their shape after denaturation?
A: Yes, many proteins can spontaneously regain their shape after denaturation.
Q: What is a prion?
A: A prion is a proteinaceous infectious agent, such as PrP, that causes spongiform encephalopathies.
Q: What are some famous diseases caused by prions?
A: Some famous prion diseases include BSE (Bovine Spongiform Encephalopathy), Scrapie, and CJD (Creutzfeldt-Jakob Disease).
Q: Do prions require encoding from nucleic acids like viruses, bacteria, or fungi?
A: No, prions do not require encoding from nucleic acids.
What are the four levels of protein structure?
A: The four levels of protein structure are:
Primary structure: The sequence of amino acid residues.
Secondary structure: Includes structures like the α-helix. 3D shape that the protein takes due to hydrogen bonding between the amino acid
Tertiary structure: The folding of the polypeptide chain into a three-dimensional shape.
Quaternary structure: The assembly of multiple subunits into a functional protein.
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