Zinc ion coordination as a modulating factor of the ZnuA histidine-rich loop flexibility: A molecular modeling and fluorescence spectroscopy study

► Fluorescence data indicate that the His-loop of ZnuA interacts with Zn+2 ions. ► The ZnuA structural model proposed validates these spectroscopic findings. ► It is proposed that a zinc loaded His-loop may facilitate the ZnuA-ZnuB recognition.