Download Primary Secondary Tertiary Quaternary Structure Notes and Questions

Primary-Secondary-Tertiary-Quaternary Structure Notes and Questions
There are four different levels of structures: primary, secondary, tertiary and quaternary
structure.
The primary structure is the sequence of amino acids in the protein or peptide (onedimensional).
-
Is like the order of letters in a long word
o Determined by inherited genetic info.
The sequence of amino acids in a polypeptide chain w/reference to the locations of
any disulfide bonds
o Can be thought of as a complete description of all of the covalent bonding in a
polypeptide chain or protein
Secondary structure – coiled resulting from hydrogen bonds between repeating constituents of
the polypeptide backbone
-
α helix
β pleated sheet (folded)
o α helix and β pleated are the most common but there are others
The folds and coils are the result of hydrogen bonds along the polypeptide backbone
o Check out the hydrogen bonds in the following diagram in the α helix and β
pleated sheet
1. Does a single polypeptide or protein consist of just one type of secondary structure?
2. For the α helix and β pleated sheet is each peptide bond cis or trans?
3. The helix is stabilized by hydrogen bonding between which two functional groups?
4. The pleated sheet is stabilized by hydrogen bonding between which functional groups?
Tertiary structure is determined by interactions between R groups, rather than interactions
between backbone constituents
- Interactions between R groups include
o Hydrophobic interaction
 Amino acids with hydrophobic (nonpolar) side chains usually
congregate in clusters at the core of the protein, out of contact with
water.
o Hydrogen Bonds
o Ionic
o Hydrophobic interactions
o Van Der Waals interactions
 Sum of the attractive or repulsive forces between molecules
 Forces between 2 permanent dipoles
 Force between a permanent dipole and a corresponding induced dipole
5. When are the secondary and tertiary structures the same?
6. Tertiary structures are largely maintained by?
Quaternary structure: Results when 2 or more polypeptide chains form one macromolecule