Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a classical glycolytic protein that can promote the fusion of phospholipid vesicles and can also play a vital role on in vivo fusogenic events. However, it is not clear how this redox enzyme, which lack conserved structural or sequence motifs related to membrane fusion, catalyze this process. In order to detect if this ability is present in other NAD(P)H dehydrogenases with available structure, spectroscopic studies were performed to evaluate the capability of alcohol dehydrogenase (ADH), glutamic dehydrogenase (GDH) and sorbitol dehydrogenase (SDH) to bind, aggregate, destabilize and fuse vesicles. Based on finite difference Poisson-Boltzmann calculations (FDPB) the protein-membrane interactions were analyzed. A model for the protein-membrane complex in its minimum free energy of interaction was obtained for each protein and the amino acids involved in the binding processes were suggested. A previously undescribed relationship between membrane destabilization and crevices with high electropositive potential on the protein surface was proposed. The putative implication of the non-specific electrostatics on NAD(P)H dehydrogenases induced membrane fusion is discussed. © 2008 Elsevier B.V. All rights reserved.

This research was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PIP 6399, RIB (Red Iberoamericana de Bioinformática), Secretaría de Ciencia y Técnica de la Universidad Nacional de Tucumán (CIUNT) 26/D-313, Argentina and FONCYT (PAE 22642). JDLR thanks to the Spanish Ministery of Health (MSyC) for the Project (FIS ISCIII PI061153).

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