Hexokinase-binding properties of the mitochondrial VDAC protein: inhibition by DCCD and location of putative DCCD-binding sites.
The outer mitochondrial membrane receptor for hexokinase binding has been identified as the VDAC protein, also known as mitochondrial porin. The ability of the receptor to bind hexokinase is inhibited by pretreatment with dicyclohexylcarbodiimide (DCCD). At low concentrations, DCCD inhibits hexokinase binding by covalently labeling the VDAC protein, with no apparent effect on VDAC channel-forming activity. The stoichiometry of [14C]-DCCD labeling is consistent with one to two high-affinity DCCD-binding sites per VDAC monomer. A comparison between the sequence of yeast VDAC and a conserved sequence found at DCCD-binding sites of several membrane proteins showed two sites where the yeast VDAC amino acid sequence appears to be very similar to the conserved DCCD-binding sequence. Both of these sites are located near the C-terminal end of yeast VDAC (residues 257-265 and 275-283). These results are consistent with a model in which the C-terminal end of VDAC is involved in binding to the N-terminal end of hexokinase.
Nakashima
R A
RA
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409.
D001665:Binding Sites; D004024:Dicyclohexylcarbodiimide / Q000378:metabolism / Q000494:pharmacology; D006593:Hexokinase / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D018272:Porins; D050994:Voltage-Dependent Anion Channels
D007473:Ion Channels; D008565:Membrane Proteins; D018272:Porins; D050994:Voltage-Dependent Anion Channels; D004024:Dicyclohexylcarbodiimide; D006593:Hexokinase