Protein Structure Flashcards
What is the definition of a protein conformation?
A three-dimensional structure adopted by proteins, crucial for their function.
What are the two main types of protein conformations?
- Fibrous
- Globular
Why is the structure of proteins important?
There is a vital link between structure and function in proteins.
What are the four standard levels of protein structure?
- Primary (1o)
- Secondary (2o)
- Tertiary (3o)
- Quaternary (4o)
What does primary structure refer to?
The order of amino acids covalently bonded in a polypeptide chain.
How are amino acid sequences commonly represented?
Using one-letter abbreviations for each amino acid.
What is the significance of the N-terminal and C-terminal in amino acid sequences?
The sequence starts with the N-terminal on the left and ends with the C-terminal on the right.
What are the three types of secondary structure in proteins?
- Alpha-helices
- Beta-sheets
- Beta turns
What is the characteristic structure of an alpha-helix?
A coiled structure where backbone atoms form hydrogen bonds.
How many amino acids are typically found in one turn of an alpha-helix?
3.6 amino acids.
What is the difference between parallel and anti-parallel beta-sheets?
- Parallel: Beta-strands go in the same direction.
- Anti-parallel: Beta-strands go in opposite directions.
What is a beta-turn?
A four-residue unit that turns 180 degrees in the protein structure.
What is a protein motif?
A stable group of secondary structures that contributes to protein function.
What defines tertiary structure in proteins?
The overall three-dimensional structure of a folded polypeptide, including all secondary structures.
What maintains the tertiary structure of proteins?
Non-covalent forces and disulfide bonds.
What is a prosthetic group?
A non-amino acid portion of a molecule necessary for the structure and function of a protein.
What characterizes quaternary structure?
Association of two or more independent polypeptide chains.
What is a dimer in protein structure?
A protein with two identical polypeptide chains.
What is hemoglobin’s subunit composition?
Four subunits: two alpha and two beta subunits.
What is the significance of the ‘-in’ suffix in protein names?
It indicates proteins that are not enzymes.
What suffix is typically used for enzyme names?
‘-ase’ (e.g., protease, staphylokinase).
