Visualizing the tunnel in tryptophan synthase with crystallography: Insights into a selective filter for accommodating indole and rejecting water
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- 作者：Eduardo Hilarioa ; Bethany G. Caulkinsb ; Yu-Ming M. Huangb ; 1 ; Wanli Youb ; Chia-En A. Changb ; Leonard J. Muellerb ; ; Michael F. Dunna ; ; Li Fana ;
- 关键词：TS ; tryptophan synthase from S. typhimurium ; F6 ; N-(4&prime ; -trifluoromethoxybenzoyl)-2-aminoethyl phosphate ; F9 ; N-(4&prime ; -trifluoromethoxybenzenesulfonyl)-2-aminoethyl phosphate ; PLP ; pyridoxal-5&prime ; -phosphate ; IGP ; 3-indole-D-glycerol 3&prime ; -phosphate ; G3P ; D-glyceraldehyde 3-phosphate ; E(Ain) ; the internal aldimine (Schiff base) intermediate ; E(GD1) ; the L-Ser gem diamine species ; E(Aex1) ; the external aldimine intermediate formed between the PLP cofactor and L-Ser ; E(Q1) ; the L-Ser q
- 刊名：Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
- 出版年：2016
- 出版时间：March 2016
- 年：2016
- 卷：1864
- 期：3
- 页码：268-279
- 全文大小：2223 K
文摘
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X-ray structures of a ligand threaded into the tunnel connecting the α- and β-sites.
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βPhe280 appears not to play a gating role in transfer of indole through the tunnel.
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X-ray structures and MD simulations indicate a dewetted channel.
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Hydrophobic indole freely diffuses between the α- and β-sites via the tunnel.
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Exclusion of water inhibits a deleterious side reaction in the catalytic cycle.