1. Protein Structure

2. Review of Proteins Small molecules — 20 kinds
1 amino group
1 carboxyl group
1 "R" group
Joined by peptide bonds to form polypeptide
Different sequence makes different protein

3. Proteins are amino acid polymers Many roles in the cell…
Enzymes
Hormones
Structure (muscle, hair, nails)
Cell membrane pumps and channels

4. The “R” Group Placeholder
Amino Acid
Carboxylic Acid Group
Amine Group     R
“Alpha” Carbon
The “R” Group Placeholder

5. Levels of Protein Structure
Like describing a knot by starting with the strands of the rope
Primary: The amino acid sequence
Secondary: Coiling or folding
Tertiary: folding, kinking, twisting entire structure
Quaternary: Two or more chains together

6. Primary: The amino acid sequence.
This is simply a list of the actual sequence of amino acids in the "backbone" of the protein.
You just start at one end and read off the names of the amino acids in sequence and you have described the primary sequence.

7. Secondary: Coiling of the chain.
The "R" groups get in each other's way and force a twisting of the chain into a coil.

8. Tertiary: Coiling of the coil.
Like if you were to take a screen door spring and tie it in a super knot

9. Quaternary: Two or more chains together
Not all proteins have this level.
It only applies to proteins composed of two or more separate polypeptides glued together.
It refers to how the individual polypeptides are attached.

10. Quaternary Structure

11. Illustration of Protein Structure
Primary (Sequence)
Tertiary (Bending)
Quaternary (Layering)
Secondary (Coiling)

12. Denaturation- When an unfavorable change causes a protein to unravel and lose its normal shape
A change in temperature
A change in pH
Some other environmental factor