Surface plasmon resonance and nuclear magnetic resonance studies of ABAD-Abeta interaction.
Abeta binding alcohol dehydrogenase (ABAD) is an NAD-dependent mitochondrial dehydrogenase. The binding between ABAD and Abeta is likely a direct link between Abeta and mitochondrial toxicity in Alzheimer's disease. In this study, surface plasmon resonance (SPR) was employed to determine the temperature dependence of the affinity of the ABAD-Abeta interaction. A van't Hoff analysis revealed that the ABAD-Abeta association is driven by a favorable entropic change (DeltaS = 300 +/- 30 J mol-1 K-1) which overcomes an unfavorable enthalpy change (DeltaH = 49 +/- 7 kJ/mol). Therefore, hydrophobic interactions and changes in protein dynamics are the dominant driving forces of the ABAD-Abeta interaction. This is the first dissection of the entropic and enthalpic contribution to the energetics of a protein-protein interaction involving Abeta. SPR confirmed the conformational changes in the ABAD-Abeta complex after Abeta binding, consistent with differences seen in the crystal structures of free ABAD and the ABAD-Abeta complex. Saturation transfer difference (STD) NMR experiments directly and unambiguously demonstrated the inhibitory effect of Abeta on the ABAD-NAD interaction. Conversely, NAD inhibits the Abeta-ABAD interaction. Binding of Abeta and binding of NAD to ABAD are likely mutually exclusive. Thus, Abeta binding induces conformational and subsequently functional changes in ABAD, which may have a role in the mechanism of Abeta toxicity in Alzheimer's disease.
Yan
Yilin
Y
Department of Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Liu
Yangzhong
Y
Sorci
Mirco
M
Belfort
Georges
G
Lustbader
Joyce W
JW
Yan
Shirley ShiDu
SS
Wang
Chunyu
C
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000737:chemistry*; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D020349:Surface Plasmon Resonance; D013696:Temperature; D013816:Thermodynamics
D016229:Amyloid beta-Peptides; D015094:3-Hydroxyacyl CoA Dehydrogenases; C108634:HSD17B10 protein, human