1. Proteins
The most important biochemicals in cells are proteins (enzymes)
Protect organisms from disease
Extract energy from food
Move essential cellular components
Responsible for vision, taste and smell
Proteins are the molecular machinery of the cell.
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2. Proteins Day 1 Proteins are made of amino acids (aa)
The base structure is the same, but each a.a. has a different side chain
There are 20 a.a. in humans
Each has different properties
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3. Globular Proteins
Are compact, roughly spherical structures with folds and grooves
Enzymes: globular proteins that speed up biochemical reactions
Ex: Hemoglobin, antibodies, and hormones
Carry most of the work done by cells
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4. Globular Proteins
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5. Fibrous Proteins
Structural components of cells and tissue are made of proteins that form fibers.
The fibrous proteins are the cables, girders, bricks and mortar of organisms.
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6. Collagen
Silk Fiber

7. Proteins Day 1 A protein has 4 structure categories:
Primary: Basic linkage of amino acids
Carbon of one links to N of other in chain
Secondary: alpha helix and beta pleated sheet
Both use hydrogen bonding
Tertiary: Intermolecular bonding
Salt bridge, hydrophilic/hydrophobic, polar/nonpolar, disulfur linkage
Quaternary: protein-protein interaction
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8. Primary Structure
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9. Making a protein
We are going to make a protein called Vasopressin (ADH)
It is involved in kidney function, formation of memory, and can increase blood pressure
The sequence of amino acids is cys-tyr-phe-gln-asn-cys-pro-arg-gly
Each team will make 1 amino acid and we will link them together.
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10. Making a protein questions
Questions to ask:
What happens when 1 amino acid links to another?
Ans: Water is released, peptide bond formed
2. Looking at the linkage of only 9 amino acids, how complicated do you think a model of a typical protein (100s – 1000s of amino acids) would be?
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11. 2°: The Helix

12. 2°: Pleated Sheet

13. Tertiary Structure Check out http://fold.it
Each protein has a unique 3D shape called tertiary structure
Results from the bends and folds the peptide chain makes to achieve the lowest possible energy.
Check out
Bonding is from sidechain (R group) interactions

17. Tertiary Structure Hydrogen Bond Salt Bridge Hydrophobic Bond
Disulfide Bond

18. Quaternary Structure Binds several different proteins together
This can be through a variety of interactions (sulfur linkages, hydrogen bonding, etc)
Often a process in the body needs several proteins coordinated together to work