Document Type
Article
Publication Date
2-2024
Abstract
Recent clinical data have identified infant patients with lethal ITPA deficiencies. ITPA is known to modulate ITP concentrations in cells and has a critical function in neural development which is not understood. Polymorphism of the ITPA gene affects outcomes for both ribavirin and thiopurine based therapies and nearly one third of the human population is thought to harbor ITPA polymorphism. In a previous site-directed mutagenesis alanine screen of the ITPA substrate selectivity pocket, we identified the ITPA mutant, E22A, as a gain-of function mutant with enhanced ITP hydrolysis activity. Here we report a rational enzyme engineering experiment to investigate the biochemical properties of position 22 ITPA mutants and find that the E22D ITPA has two- and four-fold improved substrate selectivity for ITP over the canonical purine triphosphates ATP and GTP, respectively, while maintaining biological activity. The novel E22D ITPA should be considered as a platform for further development of ITPA therapies.
Original Publication Title
The Protein Journal
Volume
43
Issue
1
First Page
62
Last Page
71
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Burgis, Nicholas E.; VanWormer, Kandise; Robbins, Devin; and Smith, Jonathan, "An ITPA Enzyme with Improved Substrate Selectivity" (2024). Chemistry and Biochemistry Faculty Publications. 32.
https://dc.ewu.edu/chem_fac/32
Comments
DOI: https://doi.org/10.1007/s10930-023-10162-0