Motion of the Zinc Ions in Catalysis by a Dizinc Metallo-β-Lactamase

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Format of Original

2 p.

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American Chemical Society

Source Publication

Journal of the American Chemical Society

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Original Item ID

doi: 10.1021/ja902534b


We report rapid-freeze-quench X-ray absorption spectroscopy of a dizinc metallo-β-lactamase (MβL) reaction intermediate. The Zn(II) ions in the dinuclear active site of the S. maltophilia Class B3 MβL move away from each other, by ∼0.3 Å after 10 ms of reaction with nitrocefin, from 3.4 to 3.7 Å. Together with our previous characterization of the resting enzyme and its nitrocefin product complex, where the Zn(II) ion separation relaxes to 3.6 Å, these data indicate a scissoring motion of the active site that accompanies the ring-opening step. The average Zn(II) coordination number of 4.5 in the resting enzyme appears to be maintained throughout the reaction with nitrocefin. This is the first direct structural information available on early stage dizinc metallo-β-lactamase catalysis.


Accepted version. Journal of the American Chemical Society, Vol. 131, No. 33 (August 2009): 11642-11643. DOI. © 2009 American Chemical Society. Used with permission.

Brian Bennett was affiliated with Medical College of Wisconsin at the time of publication.