76 by: Kosisochakwu Okoli
Student – Kosisochukwu Okoli
Enzyme – Tryptophan Synthase 4.2.1.20
Tryptophan Synthase is commonly found in Bacteria, Archaea, Protists, Fungi, and Plants. The enzyme is absent in animals.
What does it do? Tryptophan synthase is an enzyme that catalyzes the final two steps in the biosynthesis of the amino acid tryptophan. It is a bifunctional enzyme composed of two subunits: the α-subunit and the β-subunit. The α-subunit catalyzes the cleavage of indole-3-glycerol phosphate to indole, while the β-subunit catalyzes the condensation of indole with serine to form tryptophan (Miles, 2001).
Interesting Fact – The active sites of the neighboring alpha and beta subunits have a distance of ~25 Angstrom between them. A tunnel having a diameter similar to that of the indole intermediate connects both subunits. The tunnel guides indole from the alpha active site into the beta active site, preventing indole from escaping into the surrounding solvent. (Hyde et al., 1988)
References
Buller, A. R., van Roye, P., Murciano-Calles, J., & Arnold, F. H. (2016). Tryptophan Synthase Uses an Atypical Mechanism To Achieve Substrate Specificity. Biochemistry, 55(51), 7043–7046. https://doi.org/10.1021/acs.biochem.6b01127
Hyde, C. C., Ahmed, S. A., Padlan, E. A., Miles, E. W., & Davies, D. R. (1988). Three-dimensional structure of the tryptophan synthase alpha 2 beta 2 multienzyme complex from Salmonella typhimurium. The Journal of biological chemistry, 263(33), 17857–17871.
Miles E. W. (2001). Tryptophan synthase: a multienzyme complex with an intramolecular tunnel. Chemical record (New York, N.Y.), 1(2), 140–151. https://doi.org/10.1002/tcr.4
O’Rourke, K. F., Gorman, S. D., & Boehr, D. D. (2016). Biophysical and computational methods to analyze amino acid interaction networks in proteins. Computational and Structural Biotechnology Journal, 14, 245–251. https://doi.org/10.1016/j.csbj.2016.06.002
Watkins-Dulaney, E., Straathof, S., & Arnold, F. (2021). Tryptophan Synthase: Biocatalyst Extraordinaire. Chembiochem: A European Journal of Chemical Biology, 22(1), 5–16. https://doi.org/10.1002/cbic.202000379
