Phospholipid bilayer Membrane

Aris Kaksis Riga Stradin's University 2014

Permission is given to copy this script freely for
non-profit educational use.
Eric Martz, 1996 Dept. Microbiology, University
of Massachusetts, Amherst MA US 01003-5720.
emartz@microbio.umass.edu


Contents:

  • I. Phosphatidyl Cholin - Lecithin
  • II. CrystallinePhospholipid tetramer BILAYER FORMATION
  • III. ROTATE SandwichWIEV Crystalline Bilayer
  • IV.Gele Bilayer Sandwich
  • V.Fluid Bilayer Sandwich
  • VI. Show Top Slice W/O Water

  • I. Phosphatidyl Choline - Lecithin

         Phospho lipids are major components building units of lipid
    bilayer membrane. Phosphatidyl Choline Phosphatidyl Choline is
    two Fatty Acid Lipid - Diglyceride ester with
    Phosphate and Phosphate ester with Choline
    PALMITOYL OLEOYL PHOSPHATIDYL CHOLINE
    spacefilling model with charge + at Cholin nitrogen N
    and negative charge - at Phosphate PO4-group
    (relative atomic diameters as van der Walls radii)
    PALMITOYL OLEOYL PHOSPHATIDYL CHOLINE
    wireframe 80 units model (shows only bonds,
    not atoms C carbons and H hydrogen)
    PALMITOYL OLEOYL PHOSPHATIDYL CHOLINE
    wireframe 40 units model (shows only bonds,
    not atoms C carbons and H hydrogen)
    PALMITOYL OLEOYL PHOSPHATIDYL CHOLINE
    is composed of a glycerol backbone glycerole linked to a phosphate
    and to phosphate linked to choline choline
    The Glycerol is esterifide to two Fatty Acids
    OLEIC ACID (18:1) oleate oleic acid salt
    The glycerol is esterified to two fatty acids
    OLEIC ACID (18:1) and
    PALMITIC ACID (16:0, yellow) palmitate palmitic acid salt
    PALMITOYL OLEOYL PHOSPHATIDYL CHOLINE (PC)
    spacefilling model (relative atomic diameters).
    HYDROGEN WILL BE OMITTED TO SIMPLIFY THE DISPLAY.
    Spacefiil off and wireframe 40 model .

    II. Crystalline bilayer Phospholipid tetramer. Five Phosphatidyl Choline tetrades in row Crystalline Bilayer Sandwich

    A CRYSTALLINE bilayer is constructed from a single Phospholipid layer
    sticking in compact tetramer.Yellow unsaturated,gray for saturated arms.
    We'll highlight the terminal methyl groups carbons.
    DIFFERENTLY COLOR 4 PHOSPHOLIPID IN A ROW..
    FOUR Phosphatidyl Cholines (PC). ASSEMBLE TETRAD green; yellow
    Notice how the white leg of one PC fits between the legs of the other green; yellow
    So on fourth magenta TURN TETRAD UPRIGHT
    AND ROTATE
    Nitrogens (in choline) and phosphoruses are enlarged. This is palmitic yellow gray for saturated arms
    ROTATE SO WE LOOK DOWN ON TOPS. zoom 200
    Nitrogens (in choline) and phosphoruses are enlarged. 5 phospholipid tetrads are copied into a tight-fitting row of 20 phospholipid molecules. Multicolored spacefilled slice. Skript BACARS . refres refres Notice the position of the nitrogens relative to the phosphorus. BilayerSlice ...Remove LIPIDS palmitic and oleic. ADD LIPIDS SpaceFill palmitic and oleic and green water . Most of the phospholipids are cut away to reveal every 4th phospholipid in the middle row.

    III. ROTATE TO SANDWICH VIEW CRYSTALLINE. CRYSTALLINEoff HOHCRYSTALLINE

    Highly polar water and ice molecule Water H2O
         Part of the bottom water layer has been cut away. The bilayer row is copied into 5 rows, forming two leaflets of 100 phospholipids each, 200 phospholipids total is shown at left. The bilayer row is copied into 5 rows, forming two leaflets of 100 phospholipids each, 200 phospholipids total.
         Refresh the model then contains 30,000 atoms. 5,000 water molecules were added. Notice the position of the nitrogens relative to the phosphorus. ADD LIPIDS. This is palmitic acid. Yellow gray for saturated arms. Part of the bottom water layer has been cut away. <><|><> Water layers have been omitted completely and spacefill Phosphatidyl bilayer presented Most of the phospholipids are cut away to reveal every 4th phospholipid in the middle row.
    to get rid of funny colors. After completion of two 10 x 10 leaflets of phospholipids. ..<=>..

    IV. Gele Bilayer Sandwich Gele
    Select Phosphorus. Select Nitrogen.
    ADD LIPIDS This is palmitic. yellow gray for saturated arms.
    Part of the bottom water layer has been cut away
    restrict not water
    Most of the phospholipids are cut away
    to reveal eevery 4th phospholipid in the middle row spcefill

    V. Fluid Bilayer Sandwich Fluid
    Select Phosphorus. Select Nitrogen.
    ADD LIPIDS This is palmitic. yellow gray for saturated arms.
    Part of the bottom water layer has been cut away
    restrict not water
    Most of the phospholipids are cut away
    to reveal eevery 4th phospholipid in the middle row spcefill

    VI. SHOW TOP SLICE W/O WATER
    SliceTopWater SHOW SLICE BILAYER WITHOUT WATER The row is copied to form a bilayer row of 40 phospholipids ZOOM DOWN TO MAKE ROOM FOR WATER SHOW WATER WIREFRAME and water molecules (bluegreen) are fitted against each surface. SHOW WATER SPACEFIL SHOW SPACEFILL ALL BACK TO WIREFRAME Here are just the 40 phosphorus P atoms so you can see how they are arrangedhorizontally. arranged on top wiev.
    References
    Eric Marz (1997) Membrane. Maschusets University USA.Back to the Index...