BIOC 4580 Midterm: BIOC 4580 Lecture 4

• School: University of Guelph
• Department: Biochemistry
• Course: BIOC 4580
• Professor: George Harauz

Document Summary

Important: pc and spm look similar as space-filling models, but have overall different shapes. Transverse diffusion (flip-flop: lateral diffusion ((cid:2778)(cid:2777) (cid:2784)(cid:4667) fast- measured by frap, hop (diffusion shows microdomains or (cid:862)(cid:272)o(cid:396)(cid:396)als(cid:863) due to (cid:272)ytoskeleto(cid:374))- vey fast (1 um/s) Frap used to measure lateral diffusion of membrane components. With time, unbleached phospholipids diffuse into bleached area measure rate of fluorescence. ** i(cid:374) a li(cid:448)e (cid:272)ell, diffusio(cid:374) is (cid:396)est(cid:396)i(cid:272)ted to (cid:862)(cid:272)o(cid:396)(cid:396)als(cid:863) o(cid:396) do(cid:373)ai(cid:374)s fo(cid:396)(cid:373)ed (cid:271)y u(cid:374)de(cid:396)lyi(cid:374)g (cid:272)ytoskeletal netwrodk: transverse diffusion ((cid:2778)(cid:2777)(cid:4667) very slow on its own (days) because of large activation energy, faster with proteins (flippases and floppases) Flippase moves pe and ps from outer to cytosolic leaflet- energy(atp)-dependent. Cytoskeletal interactions help keep ps and pe in the inner leaflet. Floppase moves phospholipids from cytosolic to outer leaflet- energy(atp)-dependent. Scramblase moves lipids in either direction, towards equilibrium. Slow flip-flop helps to maintain lipid asymmetry (not catalyzed flip-flop) Includes flexing and rotation of fatty acid tails.