3-D Structure of Proteins Flashcards
What is the primary organization of proteins?
Amino acid sequence + disulfide bonds
What is the secondary organization of proteins?
Regular recurring arrangements of adjacent amino acids
What is the tertiary organization of proteins?
Arrangement of the total protein, the complete 3D structure
What is the quaternary organization of proteins?
The arrangement of multiple protein subunits
When a protein is denatured, what bonds aren’t broken?
Disulfide bonds
Peptide bonds
What is a domain, with regards to proteins?
A contiguous region with a distinct function
What are some examples of protein domains?
DNA binding
Transmembrane
Calcium binding
Peptide bonds and disulfide bonds are both which type of bond?
Covalent
Peptide bonds are ___ and ___.
Planar and rigid
Which amino acid acts as the “oxidative stress sensor”?
Cysteine
What are the 3 major secondary structure types in proteins?
Alpha helix
Beta pleated sheet
Beta turn
In alpha helices, where do the peptide bonds align?
Along the long axis
In alpha helices, where are the R groups?
Sticking out of the sides
Each turn in alpha helices uses about how many amino acids?
About 3.6
How are alpha helices stabilized?
Lots of hydrogen bonding
Which amino acid is generally a “helix breaker”?
Proline
What things are alpha helix destabilizers?
- A string of several basic or acidic amino acids
- A string of several amino acids with bulky side groups
- Amino acids 3-4 residues apart which cannot interact
- Proline residues
- A string of glycine residues
How are beta pleated sheet chains arranged?
May be in parallel or anti-parallel fashion
What is beta pleated sheet?
Extended arrangement of polypeptides
What hold the adjacent chains together in beta pleated sheet?
Hydrogen bonds
Beta turns contain which amino acid?
Proline
In which conformation is proline found in beta turn?
The cis conformation
What converts proline from the trans to the cis conformation?
Proline isomerase