Document Type
Article
Publication Date
1-2026
Publication Title
Acta Crystallographica Section F-Structural Biology Communications
Abstract
Here, we report the X-ray structural analysis of dihydroorotase from Methanococcus jannaschii co-crystallized with dihydroorotate at pH 6.5. The crystals are isomorphous with the crystals of the apoenzyme, with space group P3221 and unit-cell dimensions a = b = 111.4, c = 101.2 Å. The structure was refined to R = 0.169 and Rfree = 0.186 at a resolution of 1.87 Å at room temperature. During crystallization the degradative reaction took place, and the electron density in the active site corresponds to the substrate carbamoyl aspartate. Carbamoyl aspartate interacts with the protein in the active site in a manner similar to that observed for Escherichia coli and human dihydroorotases. However, the flexible loop (residues 140–151) adopts both conformations in the crystal, loop-out and loop-in, with the loop-out conformation having higher occupancy. This contrasts with our expectations for the flexible loop to be exclusively in the loop-in conformation, which is the conformation that it adopts to stabilize the binding of the substrate in the known systems. Additional studies with substrate analogs that resemble carbamoyl aspartate and different crystallization conditions would provide further insight into the conformation of the flexible loop in this system.
Repository Citation
Vitali, Jacqueline; Nix, Jay C.; Newman, Haley E.; and Colaneri, Michael J., "Crystal Structure of Methanococcus jannaschii dihydroorotase with Substrate Bound" (2026). Physics Faculty Publications. 441.
https://engagedscholarship.csuohio.edu/sciphysics_facpub/441
DOI
10.1107/S2053230X25010556
Version
Publisher's PDF
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Volume
82
Comments
We thank Cleveland State University for two Undergraduate Student Research Awards (JV) and an Undergraduate Research Award (HEN) that supported this research in part. Beamline 4.2.2 of the Advanced Light Source, a DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231, is supported in part by the ALS-ENABLE program funded by the National Institutes of Health, National Institute of General Medical Sciences, grant P30 GM124169-01.