8EYP

Joint X-ray/neutron structure of Salmonella typhimurium tryptophan synthase internal aldimine from microgravity-grown crystal

Summary for 8EYP

• Entry DOI: 10.2210/pdb8eyp/pdb
• Descriptor: Tryptophan synthase alpha chain, Tryptophan synthase beta chain, SODIUM ION, ... (4 entities in total)
• Functional Keywords: beta-elimination, plp-dependent, alpha2beta2-tetramer, lyase
• Biological source: Salmonella enterica subsp. enterica serovar Typhi; More
• Total number of polymer chains: 2
• Total formula weight: 71868.78

Authors

Drago, V.N.,Kovalevsky, A.,Blakeley, M.P.,Forsyth, V.T.,Mueser, T.C. (deposition date: 2022-10-28, release date: 2024-02-14, Last modification date: 2024-05-08)

Primary citation

Drago, V.N.,Devos, J.M.,Blakeley, M.P.,Forsyth, V.T.,Parks, J.M.,Kovalevsky, A.,Mueser, T.C.
Neutron diffraction from a microgravity-grown crystal reveals the active site hydrogens of the internal aldimine form of tryptophan synthase.
Cell Rep Phys Sci, 5:-, 2024

PubMed Abstract: Pyridoxal 5'-phosphate (PLP), the biologically active form of vitamin B, 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.

PubMed: 38645802
DOI: 10.1016/j.xcrp.2024.101827

Experimental method

NEUTRON DIFFRACTION (2.1 Å)
X-RAY DIFFRACTION (1.8 Å)