1. Chapter 5.3: Actin, Myosin, and Molecular Motors CHEM 7784 Biochemistry Professor Bensley

2. CHAPTER 5.3 Actin, Myosin, and Molecular Motors –Molecular mechanism of muscle movements Today’s Objectives: To learn and understand

3. Functions of Globular Proteins Storage of ions and molecules –myoglobin, ferritin Transport of ions and molecules –hemoglobin, serotonin transporter Defense against pathogens –antibodies, cytokines Muscle contraction –actin, myosin Biological catalysis –chymotrypsin, lysozyme

4. Muscle Structure Muscle fiber: large, single, elongated, multinuclear cell Each fiber contains about 1,000 myofibrils

5. Myofibril Contains Thin and Thick Filaments Thick filaments are aggregates of protein myosin Thin filaments are aggregates of protein actin

6. Myosin Thick Filaments Slide along Actin Thin Filaments

7. Actomyosin Cycle Video #1 Video #2

8. Chapter 5: Summary how to quantitatively analyze binding data how myoglobin stores oxygen how hemoglobin transports O 2, protons, and CO 2 the basics of how muscle works in contraction In this chapter, we learned about: