3.2 proteins mini lecture radjewski. major functions of proteins: enzymes—catalytic proteins...
TRANSCRIPT
![Page 1: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/1.jpg)
3.2 Proteins
Mini LectureRadjewski
![Page 2: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/2.jpg)
Major functions of proteins:• Enzymes—catalytic proteins
• Defensive proteins (e.g., antibodies)
• Hormonal and regulatory proteins—control physiological processes
• Receptor proteins—receive and respond to molecular signals
• Storage proteins store amino acids
• Structural proteins—physical stability and movement
• Transport proteins carry substances (e.g., hemoglobin)
• Genetic regulatory proteins regulate when, how, and to what extent a gene is expressed
![Page 3: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/3.jpg)
Protein monomers are amino acids.• Amino and carboxylic acid functional groups
allow them to act as both acid and base.• The R group differs in each amino acid.
![Page 4: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/4.jpg)
• Only 20 amino acids occur extensively in the proteins of all organisms.
• They differ by their R groups.
![Page 5: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/5.jpg)
![Page 6: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/6.jpg)
![Page 7: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/7.jpg)
![Page 8: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/8.jpg)
![Page 9: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/9.jpg)
![Page 10: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/10.jpg)
• Oligopeptides or peptides—short polymers of 20 or fewer amino acids (some hormones and signaling molecules)
• Polypeptides or proteins range in size from insulin, which has 51 amino acids, to huge molecules such as the muscle protein titin, with 34,350 amino acids.
![Page 11: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/11.jpg)
How to make a protein
• Amino acids are linked in condensation reactions to form peptide linkages or bonds.
![Page 12: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/12.jpg)
Primary structure of a protein—the sequence of amino acids
![Page 13: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/13.jpg)
Secondary structure—regular, repeated spatial patterns in different regions, resulting from hydrogen bonding
• • α (alpha) helix—right-handed coil
• β (beta) pleated sheet—two or more polypeptide chains are extended and aligned
![Page 14: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/14.jpg)
Tertiary structure—polypeptide chain is bent and folded; results in the definitive 3-D shape
• The outer surfaces present functional groups that can interact with other molecules.
![Page 15: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/15.jpg)
Interactions between R groups determine tertiary structure.
• Disulfide bridges hold a folded polypeptide together
• Hydrogen bonds stabilize folds • Hydrophobic side chains can aggregate• van der Waals interactions between
hydrophobic side chains• Ionic interactions
![Page 16: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/16.jpg)
• Quaternary structure—two or more polypeptide chains (subunits) bind together by hydrophobic and ionic interactions, and hydrogen bonds.
• These weak interactions allow small changes that aid in the protein’s function.
![Page 17: 3.2 Proteins Mini Lecture Radjewski. Major functions of proteins: Enzymes—catalytic proteins Defensive proteins (e.g., antibodies) Hormonal and regulatory](https://reader030.vdocuments.net/reader030/viewer/2022032708/56649e7e5503460f94b80cfe/html5/thumbnails/17.jpg)
Factors that can disrupt the interactions that determine protein structure (denaturing):
• Temperature • Concentration of H+ • High concentrations of polar substances • Nonpolar substances