BSCI 330 Chapter Notes - Chapter 16: Cell Cortex, Centromere, Spindle Apparatus

• School: University of Maryland
• Department: Biological Sciences Program
• Course: BSCI 330
• Professor: Ibrahim Ades

Document Summary

Actin based motor proteins are members of the myosin superfamily. Myosin ii: skeletal muscle myosin: elongated protesin, 2 heavy chains and two copies of each of two light chains (4 light chains total?) Heavy chain: globular head domain at n terminus (force generating machinery, extended coiled coil amino acid sequence (mediates dimerization) The two light chains bind close to n terminus. Tail-tail interacts for large, bipolar, thick filaments. Long coiled coil bundles with tails of other myosin molecules: several hundred myosin heads oriented in opposite directs at two ends of the thick filament. Each myosin head binds to and hydrolyzes atp: uses energy to walk towards plus end of each actin filament, hence, actin filaments moving towards their minus end. Opposing head orientation in thick filament = efficiently slides pairs of actin filaments towards each other (shortening muscle) Skeletal mus(cid:272)le: a(cid:272)ti(cid:374) fila(cid:373)e(cid:374)ts alig(cid:374)ed i(cid:374) (cid:858)thi(cid:374) fila(cid:373)e(cid:374)t(cid:859) arrays surrou(cid:374)ded (cid:271)y (cid:373)yosin thick filaments.