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Mercury complexes of thionicotinamide adenine dinucleotide.
Biochimica Et Biophysica Acta
|May 3, 1978
Summary
Researchers created mercury complexes with thionicotinamide adenine dinucleotide (TNAD+). Mercury binds to TNAD+ via its thio-keto group, confirmed by spectroscopy and X-ray diffraction studies on mitochondrial malate dehydrogenase.
Area of Science:
- Biochemistry
- Chemical Biology
- Structural Biology
Background:
- Thionicotinamide adenine dinucleotide (TNAD+) is a NAD+ analog.
- Mercury compounds are known enzyme inhibitors and toxins.
- Understanding metal-ligand interactions is crucial in biochemistry.
Purpose of the Study:
- To synthesize and characterize mercury complexes of TNAD+.
- To investigate the binding site of mercury on TNAD+.
- To explore the interaction of mercury-TNAD+ complexes with enzymes.
Main Methods:
- Complex synthesis using mercury salts (HgSO4, Hg(CH3COO-)2).
- Optical absorption spectroscopy for electronic structure analysis.
- X-ray diffraction of enzyme crystals soaked in complex solutions.
Main Results:
- Formation of 1:1 mercury-TNAD+ complexes confirmed.
- Spectroscopic data suggest mercury binding to the thio-keto group of TNAD+.
- X-ray diffraction reveals mercury-TNAD+ complex binding to mitochondrial malate dehydrogenase, with distinct patterns from mercury alone.
Conclusions:
- Mercury selectively binds to the thio-keto group of TNAD+.
- The mercury-TNAD+ complex interacts with mitochondrial malate dehydrogenase.
- This interaction differs from the binding of mercury compounds alone, suggesting specific complex-enzyme recognition.