LPandiscia+log

November 18: Merck Index Image

Sigma Image

November 7: Kinnunen, P. K., //et al.// The Journal of Biological Chemistry, 1994, 269, 1770-1774. [|Publication]
 * Assignment #2**
 * Evidence for Two Distinct Binding Acidic Phospholipid-binding Sites in Cytochrome //c//**
 * [Full Marks JCB]**
 * Cytochrome //c// bound to liposomes induced conformational changes of the protein.
 * At neutral pH, both the pH and ionic strength effect the structure of cytochrome //c// and the protonation of the acidic phospholipids.
 * Increasing the cardiolipin (CL) /phosphatidylcholinel (PC) molar ratio increases the extent of membrane-associated cyt //c//.
 * As the molar ratio of phosphatidylglycerol (PG) /PC is increased, the extent of dissociation of cyt //c// from the liposomes by ATP decreases.
 * The cause of protein dissociation from the membrane is due to the amount of PC.
 * By increasing the amount of CL in liposomes, the dissociation of cytochrome //c// from the liposomes by NaCl decreases.
 * When the amount of CL increases in liposomes, the degree of protonation of CL also increases. NaCl now has a harder time dissociating the protein from the liposomal surface.
 * In order to deprotonate an acidic phospholipid with an increasing molar ratio, the pH value must increase. NaCl is now able to dissociate the protein from the liposomal surface and the mode of binding can be considered electrostatic.
 * Binding at site A ("anion") occurs via electrostatic interactions while binding at site C ("cardiolipin") occurs via hydrogen bonding. Only binding at site A can be dissociated by anions and deprotonated phospholipids.
 * In order for cytochrome //c// to bind to liposomal surfaces via site C, the acidic phospholipids must be protonated. If the ionic strength is increased, the phospholipid will be deprotonated and the binding will then occur at site A.
 * The extent of cytochrome //c// binding to CL/PC liposomes reaches saturation at 100% while binding of cyt //c// to PG/PC liposomes reaches saturation at 30% of acidic phospholipid content.
 * Even as NaCl dissociates cytochrome //c// from the liposomal surface at site A, the protonation of CL increases as the CL/PC molar ratio increases and the liposomal surface binds to site C on the protein.
 * PG and CL display different protonation behavior due to the number of protonatable groups of the phospholipids.
 * The heme of cytochrome //c// binds directly to the phosphate groups of cardiolipin. The addition of PC to cardiolipin blocks this interaction.
 * Interactions of cytochrome //c// in the electron transport chain involve site A while interactions with CL and cyt //c// occur at site C.

Sept. 23: Final project topic: Cytochrome //c// binding to liposomal surfaces
 * [This has already been covered to a large extent here JCB]**

September 30 //Melting Point:// 180 C Wolfram Alpha 178-180 C MSDS 175-180 C Merck 179-181 C Look Chem 353.8 F [|Cameo Chemicals]
 * Assignment 1: D-Camphor**

//Boiling Point// 408 C Wolfram Alpha 204 C [|Chemical Book] 209 C Merck 207.4 C Look Chem 203.8 C [|Cameo Chemicals]

//Explosion Limit// 3.5 % [|Sigma Aldrich] 4.5% Wolfram Alpha 0.6-3.5% [|Columbia Analytical Services] 0.6-4.5% [|Merck]

//Vapor Pressure// 3.999 mmHg Wolfram Alpha 4.000 mmHg Sigma Aldrich 0.072 mm Hg @ 25 C [|Chem Cas] 1.0 mm Hg @ 41.5 C [|Cameo Chemicals] 0.225 mmHg at 25°C [|Guide Chem]

//Flash Point:// 64.44 C Wolfram Alpha 65 C MSDS 66 C Merck 64 C [|Chem Cas]


 * [start adding to cheminfoval sheet and I'll grade]**