1. Protein- Secondary, Tertiary, and Quaternary Structure

2. Levels of Protein Structure

3. Proteins Functions of Proteins: 1. Structural: Muscles, Antibodies 2. Hormones: insulin, thyroxin 3. Cell Transport Proteins 4. Enzymes are Proteins Central Dogma of Biology DNA mRNAProtein Transcription Translation

4. Protein Building Blocks Amino acid structure: NH 3 – C - COOH

5. R Groups  Nonpolar  Polar  Charged  + Charged  - Charged

6. Nonpolar R Groups

8. Polar, but NOT Charged amino acids

10. Polar, Charged (Acidic) amino acids

11. Basic amino acids

12. Structure of R-group determines the chemical properties of the amino acid The polar uncharged amino acids are hydrophilic and can form hydrogen bonds The nonpolar amino acids are hydrophobic and are usually found in the center of the protein; they are also found in proteins which associated with cell membrane The electrically charged amino acids have electrical properties that can change depending on the pH Cysteine can form disulfide bond Proline has a unique structure and causes kinks in the protein chain When 2 amino acids are joined, the bond formed is called peptide bond

13. Building Proteins: The Peptide Bond

14. Peptide Bond O H C N You must be able to draw this bond, recognize this bond, and the significance of this bond.

15. Primary Structure of Proteins  The sequence of amino acids in the polypeptide chain  The sequence of R groups determine the properties of the protein  A change of a single amino acid can alter the function of the protein  Sickle Cell Anemia- caused by a change of one amino acid from glutamine to valine

16. Secondary Structure of Protein  Folding and coiling due to hydrogen bond formation between carboxyl and amino group of non-adjacent amino acid  These bonds occur between the BACKBONE of the strand of amino acids  R groups are NOT involved  Folding is due to the disulfide bond  Two common examples: alpha helix and beta pleated sheet

17. Secondary Structure of Protein

18. Folding due to Disulfide bond

19. Tertiary Structure of Protein  3-D structure resulting from the folding of 2 o structural elements  Stabilized by bonds formed between amino acid R groups  Form many shapes (globular compact proteins and fibrous elongated proteins)

20. Tertiary Structure of Proteins

21. Quaternary Structure of Protein  Multiple polypeptide chains bonded together  3-D structure due to interactions between polypeptide chains  R-group interactions, H bonds, ionic interactions  Assembled after synthesis  Only proteins with more than one subunit can have a quaternary structure

22. Quaternary Structure of Protein

23. Denaturation  Environment change (increased heat, changes in pH) proteins can unfold or “denature”  Loss of dimensional shape  loss of protein function  Sometimes able to refold back into it’s original conformation

24. Nucleic Acids DNARNA

25. Nucleic Acids  3 components to a nucleotide: a pentose sugar, a phosphate group, and a nucleotide base

26. Nucleic Acids (2 Common forms):  RNA (ribonucleic acid)  DNA (deoxyribonucleic acid)

27. DNA & RNA differ by the presence on an –OH group (RNA) or an H-group (DNA) on the 2’ carbon of the pentose sugar

28. DNA contains C, T, A, G RNA contains C, U, A, G

29. DNA: double stranded RNA: single stranded

30. When a DNA or RNA polymer is created, the bond is formed between 3’ –OH group and 5’ phosphate group  phosphodiester bond