Aspartate carboxylate-zinc interactions

Fig. 18. The carboxylaie-histidine-zinc triad represents indirect carboxylate-zinc interaction across bridging histidine. Both tautomers of histidine are observed, and the hydrogen bond stereochemistry with carboxylate (either aspartate or glutamate) is generally syn. Experimental results and theoretical calculations suggest that the carboxylate-histidine- zinc form may be in equilibrium with the carboxylic acid-histidinate- zinc form, as shown.

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