Pyridoxal 5′-phosphate (PLP), the biologically active form of vitamin B6, is an essential cofactor in many biosynthetic pathways. The emergence of PLP-dependent enzymes as drug targets and biocatalysts, such as tryptophan synthase (TS), has underlined the demand to understand PLP-dependent catalysis and reaction specificity. The ability of neutron diffraction to resolve the positions of hydrogen atoms makes it an ideal technique to understand how the electrostatic environment and selective protonation of PLP regulates PLP-dependent activities. Facilitated by microgravity crystallization of TS with the Toledo Crystallization Box, we report the 2.1 Å joint X-ray/neutron (XN) structure of TS with PLP in the internal aldimine form. Positions of hydrogens were directly determined in both the α- and β-active sites, including PLP cofactor. The joint XN structure thus provides insight into the selective protonation of the internal aldimine and the electrostatic environment of TS necessary to understand the overall catalytic mechanism.
Drago, Victoria N., et al. "Neutron diffraction from a microgravity-grown crystal reveals the active site hydrogens of the internal aldimine form of tryptophan synthase." Cell Reports Physical Science, vol. 5, no. 2, Feb. 2024. https://doi.org/10.1016/j.xcrp.2024.101827
Drago, Victoria N., Devos, Juliette M., Blakeley, Matthew P., Forsyth, V. Trevor, Parks, Jerry M., Kovalevsky, Andrey, & Mueser, Timothy C. (2024). Neutron diffraction from a microgravity-grown crystal reveals the active site hydrogens of the internal aldimine form of tryptophan synthase. Cell Reports Physical Science, 5(2). https://doi.org/10.1016/j.xcrp.2024.101827
Drago, Victoria N., Devos, Juliette M., Blakeley, Matthew P., et al., "Neutron diffraction from a microgravity-grown crystal reveals the active site hydrogens of the internal aldimine form of tryptophan synthase," Cell Reports Physical Science 5, no. 2 (2024), https://doi.org/10.1016/j.xcrp.2024.101827
@article{osti_2317765,
author = {Drago, Victoria N. and Devos, Juliette M. and Blakeley, Matthew P. and Forsyth, V. Trevor and Parks, Jerry M. and Kovalevsky, Andrey and Mueser, Timothy C.},
title = {Neutron diffraction from a microgravity-grown crystal reveals the active site hydrogens of the internal aldimine form of tryptophan synthase},
annote = {Pyridoxal 5′-phosphate (PLP), the biologically active form of vitamin B6, is an essential cofactor in many biosynthetic pathways. The emergence of PLP-dependent enzymes as drug targets and biocatalysts, such as tryptophan synthase (TS), has underlined the demand to understand PLP-dependent catalysis and reaction specificity. The ability of neutron diffraction to resolve the positions of hydrogen atoms makes it an ideal technique to understand how the electrostatic environment and selective protonation of PLP regulates PLP-dependent activities. Facilitated by microgravity crystallization of TS with the Toledo Crystallization Box, we report the 2.1 Å joint X-ray/neutron (XN) structure of TS with PLP in the internal aldimine form. Positions of hydrogens were directly determined in both the α- and β-active sites, including PLP cofactor. The joint XN structure thus provides insight into the selective protonation of the internal aldimine and the electrostatic environment of TS necessary to understand the overall catalytic mechanism.},
doi = {10.1016/j.xcrp.2024.101827},
url = {https://www.osti.gov/biblio/2317765},
journal = {Cell Reports Physical Science},
issn = {ISSN 2666-3864},
number = {2},
volume = {5},
place = {United States},
publisher = {Elsevier},
year = {2024},
month = {02}}