Heavy-atom effects associated with methylmercury (II) binding to rabbit glyceraldehyde-3-phosphate dehydrogenase
✍ Scribed by Martin V. Hershberger; August H. Maki
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1980
- Tongue
- English
- Weight
- 820 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
The complex of CH~3~Hg(II) with the accessible cysteines of glyceraldehyde‐3‐phosphate dehydrogenase (GAPD, EC 1.2.1.12) from rabbit muscle has been studied by phosphorescence and optically detected magnetic resonance (ODMR) spectroscopy. The wavelength dependence of the phosphorescence decay kinetics has also been measured. Comparison of CH~3~Hg(II)–GAPD with GAPD by these methods shows that a specific optically resolved tryptophan site of GAPD is perturbed by the interaction with a nearby mercury atom. The perturbation on the luminescence and ODMR properties is typical of an external heavy‐atom effect. Based on the x‐ray diffraction structure of the lobster enzyme, it is proposed that the heavy‐atom effect results from the interaction of tryptophan‐310 with CH~3~Hg(II) bound to cysteine‐281 in the rabbit muscle enzyme.