Title
Protein arginine deiminase 2 binds calcium in an ordered fashion: implications for inhibitor design
UMMS Affiliation
Department of Biochemistry and Molecular Pharmacology
Publication Date
2015-04-17
Document Type
Article
Disciplines
Biochemistry | Enzymes and Coenzymes | Medicinal-Pharmaceutical Chemistry | Therapeutics
Abstract
Protein arginine deiminases (PADs) are calcium-dependent histone-modifying enzymes whose activity is dysregulated in inflammatory diseases and cancer. PAD2 functions as an Estrogen Receptor (ER) coactivator in breast cancer cells via the citrullination of histone tail arginine residues at ER binding sites. Although an attractive therapeutic target, the mechanisms that regulate PAD2 activity are largely unknown, especially the detailed role of how calcium facilitates enzyme activation. To gain insights into these regulatory processes, we determined the first structures of PAD2 (27 in total), and through calcium-titrations by X-ray crystallography, determined the order of binding and affinity for the six calcium ions that bind and activate this enzyme. These structures also identified several PAD2 regulatory elements, including a calcium switch that controls proper positioning of the catalytic cysteine residue, and a novel active site shielding mechanism. Additional biochemical and mass-spectrometry-based hydrogen/deuterium exchange studies support these structural findings. The identification of multiple intermediate calcium-bound structures along the PAD2 activation pathway provides critical insights that will aid the development of allosteric inhibitors targeting the PADs.
DOI of Published Version
10.1021/cb500933j
Source
ACS Chem Biol. 2015 Apr 17;10(4):1043-53. doi: 10.1021/cb500933j. Link to article on publisher's site
Journal/Book/Conference Title
ACS chemical biology
Related Resources
Repository Citation
Slade DJ, Fang P, Dreyton CJ, Zhang Y, Fuhrmann J, Rempel D, Bax BD, Coonrod SA, Lewis HD, Guo M, Gross ML, Thompson PR. (2015). Protein arginine deiminase 2 binds calcium in an ordered fashion: implications for inhibitor design. Thompson Lab Publications. https://doi.org/10.1021/cb500933j. Retrieved from https://escholarship.umassmed.edu/thompson/2