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PROTEIN PHYSICS LECTURES 11-12

PROTEIN PHYSICS LECTURES 11-12. - Fibrous proteins and their functions - Membrane proteins and their functions. Globular proteins. Membrane proteins. Fibrous proteins. H-bonds (NH:::OC) & hydrophobic forces. Fibrous proteins : regular building blocks. b a collagen.

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PROTEIN PHYSICS LECTURES 11-12

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  1. PROTEIN PHYSICS LECTURES 11-12 - Fibrous proteins and their functions - Membrane proteins and their functions

  2. Globular proteins Membrane proteins Fibrous proteins H-bonds (NH:::OC) & hydrophobic forces

  3. Fibrous proteins: regular building blocks b a collagen ____________________________________ Here, we do not consider fibrous proteins made from globules (actin, etc.)

  4. Fibrous proteins: regular building blocks b a collagen

  5. b 4.8A Silk fibroin ~50

  6. ______ b

  7. _____ b

  8. a-helical coiled- coil

  9. a-helix packing

  10. collagen triple helix: 3 chains  [Gly-X-Pro]500

  11. PRO (f = -70o) PolyPRO II PolyPRO II Before PRO

  12. Collagen: assisted folding

  13. Natively non-structured fibrous proteins: Elastin: Matrix protein. Short repeats. Poor secondary structure. Chains are linked by chemically modified Lys residues. Like in rubber.

  14. Membrane proteins: transmitters heads (polar) tails tails heads (polar) H-bonds & hydrophobics ____

  15. a Bacteriorodopsin with retinal Transport of protons H+ H+ H+

  16. b Porin Transport of polar molecules

  17. + Pore in membrane: SELECTIVITY Free energy of a charge in the non-charged non-polar pore: ~ q2 / [(MEMBRWATER)1/2rPORE] ~ ~ 20 kcal/mol / rPORE(Å)

  18. Photo- synthetic center

  19. Pigments in photo- synthetic center: Electron transfer chlorophyll   Light 

  20. Tunneling P(X) ~ 10-X(Å) T-independent Frequency of vibrations (attacks): f ~ 1015/sec Successful attacks: fSUCCS.(x)~ P(x)•f, e.g.: fSUCCS.(5Å)~ 10-5+15 ~ ~ 1010/sec Atom  1Å Attenuation of electron density:

  21. - Fibrous proteins: building blocks - Membrane proteins: transmitters

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