1 / 26

Sec61/SecY Protein review

Sec61/SecY Protein review. Sec61 protein is important for the movement of proteins across the cell membrane? A signal sequence guides the protein to the Sec61 protein? A plug model was put into play by this paper?. Lipid Membrane. More characteristics.

ellery
Télécharger la présentation

Sec61/SecY Protein review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Sec61/SecY Protein review • Sec61 protein is important for the movement of proteins across the cell membrane? • A signal sequence guides the protein to the Sec61 protein? • A plug model was put into play by this paper?

  2. Lipid Membrane

  3. More characteristics • Driving Force of formation of lipid bilayer are Hydrophobic Interactions

  4. Kinds of lipids in membrane • Phospholipids • Glycolipids • cholesterol

  5. Phospholipids • PE- phosphatidyl ethanolamine • PC- phosphatidyl choline • SM- sphingomyleine • PS- phosphatidyl serine Can serve as different markers for cell

  6. Kyte Dolittle

  7. K+ Channel • Selective filter for moving potassium out of the cell • Has four identical transmembrane subunits • Each subunit has 2 transmembrane helices and a third shorter helix called the pore helix • These subunits form a central pore

  8. K+ channel

  9. Channel tilts outwards • Has a loop that forms in channel and is going to make the selectivity filter, which will only allow K+ out • Filter formed by carbonyl oxygens of the peptide backbone

  10. K+ is 1.95 A NA+ is 0.95 A • In the cell potassium will be hydrated with water and so will sodium • Bonding between these elements and water will be a specific length • Water needs to be shed in order for K+ to go through

  11. Carbonyl oxygen will act as the surrogate water • The dehydration of the ion takes energy but it is immediately made up by interactions with carbonyl oxygen • Na is too small for this mechanism and therefore is not transported out

  12. Porin • Made by up and down barrel • Either 16 are 18 beta strands make up the porin • Porin channel has a loop region in the middle of it which will act as a selective filter. 8 A in diameter • Only certain small molecules will be able to transverse the membrane

  13. Porin is made up of three channels as described

  14. Bacteriarhodopsin • 7 transmembrane alpha helices • This protein is used for transforming light to chemical energy • Proton pump

  15. Retinol • Bound in the pocket of the protein • Undergoes isomerization when light hits it from trans to cis • Bound covalently to lysine 216

  16. The mechanism

  17. Light at a certain wavelength cause change from trans to cis of retinal • Then Asp transfers proton to schiff base • This proton is then transferred to Asp 85 and then out to the extracellular space

  18. Result • Form an electrochemical gradient which is important for bacteria survival • Use for generation of energy

  19. Photosynthetic Reaction Center • L, H, M and cytochrome subunits • L and M subunits each have 5 hydrophobic transmembrane helices • H subunit has one transmembrane helice

  20. What is taking place • Transfer of light to generate energy • Players in the reaction must be arranged in a way that ensures the forward movement of the reaction • Photons absorbed by chlorophylls

More Related