Carruthers, ThomasCarr, Paul DLoh, ChoyJackson, ColinOtting, Gottfried2015-12-101433-7851http://hdl.handle.net/1885/63884Heterodinuclear metalloenzymes are an important class of metalloproteins, but determining the location of the different metal ions can be difficult. Herein we present a new NMR spectroscopy method that uses pseudocontact shifts (PCS) to achieve this without assumptions about the coordinating ligands. The approach is illustrated with the dinuclear [FeZn] complex of IMP-1, which is a prototypical metallo-β-lactamase (MβL) that confers resistance to β-lactam antibiotics. Results from single-crystal X-ray diffraction were compromised by degradation during crystallization. With [GaZn]-IMP-1 as diamagnetic reference, the PCSs unambiguously identified the iron binding site in fresh samples of [FeZn]-IMP-1, even though the two metal centers are less than 3.8 Å apart and the iron is high-spin Fe3+, which produces only small PCSs. [FeZn]-MβLs may be important drug targets, as [FeZn]-IMP-1 is enzymatically active and readily produced in the presence of small amounts of Fe3+.http://www.sherpa.ac.uk/romeo/issn/1433-7851/..."author can archive post-print (ie final draft post-refereeing). 12 months embargo" from SHERPA/RoMEO site (as at 17/10/18). This is the peer reviewed version of the following article: [Carruthers, Thomas J., et al. "Iron (III) Located in the Dinuclear Metallo‐β‐Lactamase IMP‐1 by Pseudocontact Shifts." Angewandte Chemie International Edition 53.51 (2014): 14269-14272.], which has been published in final form at [https://dx.doi.org/10.1002/anie.201408693]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions201410.1002/anie.2014086932015-12-10