Diffusion coefficient of ATP in voltage-dependent anion channel (VDAC)

Range 16 - 33 µm^2/sec
Organism Mitochondria
Reference Rostovtseva TK, Bezrukov SM. ATP transport through a single mitochondrial channel, VDAC, studied by current fluctuation analysis. Biophys J. 1998 May74(5):2365-73 DOI: 10.1016/S0006-3495(98)77945-7 abstract and p.2369 right column 3rd paragraphPubMed ID24908397
Method Abstract: "The "molecular Coulter counter" concept has been used to study transport of ATP molecules through the nanometer-scale aqueous pore of the voltage-dependent mitochondrial ion channel, VDAC. [Investigators] examine the ATP-induced current fluctuations and the change in average current through a single fully open channel reconstituted into a planar lipid bilayer...By relating the low-frequency spectral density of the noise to the equilibrium diffusion of ATP molecules in the aqueous pore, [they] calculate a diffusion coefficient D = (1.6-3.3)×10^-11 m^2/s." P.2366 left column 4th paragraph: "VDAC channels were isolated from Neurospora crassa mitochondrial outer membranes and purified according to standard methods (Mannella, 1982, Freitag et al., 1983)."
Comments Abstract: "This [value] is one order of magnitude smaller than the ATP diffusion coefficient in the bulk, but it agrees with recent results on ATP flux measurements in multichannel membranes using the luciferin/luciferase method."
Entered by Uri M
ID 116638