Journal article

Cofactor mobility determines reaction outcome in the IMPDH and GMPR (beta-alpha)(8) barrel enzymes

Gregory C Patton, Pal Stenmark, Deviprasad R Gollapalli, Robin Sevastik, Petri Kursula, Susanne Flodin, Herwig Schuler, Colin T Swales, Hans Eklund, Fahmi Himo, Par Nordlund, Lizbeth Hedstrom

Nature Chemical Biology | NATURE PUBLISHING GROUP | Published : 2011


Inosine monophosphate dehydrogenase (IMPDH) and guanosine monophosphate reductase (GMPR) belong to the same structural family, share a common set of catalytic residues and bind the same ligands. The structural and mechanistic features that determine reaction outcome in the IMPDH and GMPR family have not been identified. Here we show that the GMPR reaction uses the same intermediate E-XMP* as IMPDH, but in this reaction the intermediate reacts with ammonia instead of water. A single crystal structure of human GMPR type 2 with IMP and NADPH fortuitously captures three different states, each of which mimics a distinct step in the catalytic cycle of GMPR. The cofactor is found in two conformatio..

View full abstract


Awarded by US National Institutes of Health (NIH)

Awarded by National Science Foundation, Division of Biological Infrastructure



Funding Acknowledgements

We thank S. Andrews at the University of Sheffield for supplying the pUC plasmid carrying the E. coli K12 GMPR gene. We also are grateful for construction of pET28a GMPR by I. S. MacPherson. We also thank the staff at BESSY (Berlin, Germany) for support at beamline BL14.1. This work was supported by the US National Institutes of Health (NIH) GM54403 (L. H.) and by grants from the Swedish Research Council (P. N. and P. S.), the Swedish Cancer Society (P. N.), the Wenner-Gren Foundations (P. S.) and the Swedish Foundation for Strategic Research (P. S.). The Q-Tof Ultima mass spectrometer at the University of Illinois was purchased in part with a grant from the National Science Foundation, Division of Biological Infrastructure (DBI-0100085). Molecular graphics images were produced using the University of California, San Fransisco (UCSF) Chimera package from the Resource for Biocomputing, Visualization, and Informatics at the UCSF (supported by NIH P41 RR001081). The Structural Genomics Consortium is a registered charity (no. 1097737) that receives funds from the Canadian Institutes for Health Research, the Canadian Foundation for Innovation, Genome Canada through the Ontario Genomics Institute, GlaxoSmithKline, Karolinska Institutet, the Knut and Alice Wallenberg Foundation, the Ontario Innovation Trust, the Ontario Ministry for Research and Innovation, Merck & Co., Inc., the Novartis Research Foundation, the Swedish Agency for Innovation Systems, the Swedish Foundation for Strategic Research and the Wellcome Trust.