Structural highlights
Function
TRPB1_PYRFU The beta subunit is responsible for the synthesis of L-tryptophan from indole and L-serine (By similarity).
Publication Abstract from PubMed
Tryptophan synthase (TrpS) catalyzes the final steps in the biosynthesis of l-tryptophan from l-serine (Ser) and indole-3-glycerol phosphate (IGP). We report that native TrpS can also catalyze a productive reaction with l-threonine (Thr), leading to (2S,3S)-beta-methyltryptophan. Surprisingly, beta-substitution occurs in vitro with a 3.4-fold higher catalytic efficiency for Ser over Thr using saturating indole, despite a >82000-fold preference for Ser in direct competition using IGP. Structural data identify a novel product binding site, and kinetic experiments clarify the atypical mechanism of specificity: Thr binds efficiently but decreases the affinity for indole and disrupts the allosteric signaling that regulates the catalytic cycle.
Tryptophan Synthase Uses an Atypical Mechanism To Achieve Substrate Specificity.,Buller AR, van Roye P, Murciano-Calles J, Arnold FH Biochemistry. 2016 Dec 27;55(51):7043-7046. doi: 10.1021/acs.biochem.6b01127., Epub 2016 Dec 13. PMID:27935677[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Buller AR, van Roye P, Murciano-Calles J, Arnold FH. Tryptophan Synthase Uses an Atypical Mechanism To Achieve Substrate Specificity. Biochemistry. 2016 Dec 27;55(51):7043-7046. doi: 10.1021/acs.biochem.6b01127., Epub 2016 Dec 13. PMID:27935677 doi:http://dx.doi.org/10.1021/acs.biochem.6b01127
