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Chapter 3 Proteins. Purpose. Mostly for structure: skin, muscle, fingernails, hair. What is the “R” group?. Variable part of the amino acid Amino Acid Chart (handout). Forming/Breaking Peptide Bonds. 0. Type of Proteins. 8. Receptor Proteins Intercellular communication
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Purpose • Mostly for structure: skin, muscle, fingernails, hair
What is the “R” group? • Variable part of the amino acid • Amino Acid Chart (handout)
Type of Proteins • 8. Receptor Proteins • Intercellular communication • Bind to specific proteins (like hormones) • Receptor Proteins
Note the H-bonds (between -O of carbonyl and -H of amino):coiling and pleating
Tertiary Folding: disulfide bridges • Disulfide bridges formed between cysteine amino acids • (Look at cysteine’s structure)
Disulfide Bridges • Formed when cysteine’s sulfur join • You Tube Videos Disulfide Bonds
Use the Amino Acid Reference Sheet • Select the type of tertiary interaction as • (1) disulfide (2) ionic • (3) H bonds (4) hydrophobic • A. Leucine and valine • B. Two cysteines • C. Aspartic acid and lysine • D. Serine and threonine
ANSWERS • Select the type of tertiary interaction as • (1) disulfide (2) ionic • (3) H bonds (4) hydrophobic • A. 4 Leucine and valine • B. 1 Two cysteines • C. 2 Aspartic acid and lysine • D. 3 Serine and threonine
Fibrous Strands Like hair, nails,skin, muscle fibers Globular Blobs Like hemoglobin, insulin, hormones, antibodies Two Basic Shapes
Identify the level of protein structure • 1. Primary 2. Secondary • 3. Tertiary 4. Quaternary • A. Beta pleated sheet • B. Order of amino acids in a protein • C. A protein with two or more peptide chains • D. The shape of a globular protein • E. Disulfide bonds between R groups
Identify the level of protein structure • 1. Primary 2. Secondary • 3. Tertiary 4. Quaternary • ANSWERS • 2 Beta pleated sheet • 1 Order of amino acids in a protein • 4 A protein with two or more peptide • chains • 3 The shape of a globular protein • 3 Disulfide bonds between R groups
Video Stuff • Protein Denaturation Video (McGraw-Hill) • Interactive Animations: Protein Folding • Protein Structures Animation • No Sound,but great molecular models
Denaturation • Disruption of secondary, tertiary and quaternary protein structure by: • heat/organics (Break apart H bonds and disrupt hydrophobic attractions) • acids/ bases (Break H bonds between polar R groups and ionic bonds) • heavy metal ions (React with S-S bonds to form solids) • agitation (Stretches chains until bonds break)
NOTE: • Denaturation does not break the primary structure • Denaturation of an egg with a strong acid video
Protein Extra Credit OPP • Can bring in up to 5 labels (no repeats) for 1 point each with a protein term circled: • protein • peptide • amino
Proteins are Active • DO PROTEIN ACTIVITY