Steve Ealick's Research Group

TenI from Bacillus subtilis

PDB file:

1YAD native TenI

*3QH2 complexed with product 2-(2-carboxy-4-methylthiazol-5-yl)ethyl phosphate (cThz-P)


B. subtilis TenI is a 22,783 Da protein that is not essential for growth in thiamin containing media. In Bacillis subtilis, TenA and TenI are part of the thiazole biosynthetic operon (TenA-TenI-ThiO-ThiS-ThiG-ThiF-ThiD). In the original 2005 paper, the function of TenI was unknown; however we now know that it accelerates the production of thiazole and functions as a thiazole tautomerase.

The TenI momoner has (βα)8 barrel fold. The monomer consists of a mainly hydrophobic core formed by residues from the β-strands that point into the interior of the barrel.

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The TenI crystal structure consists of two (βα)8 barrel dimers, with the barrel axes for each dimer oriented approximately parallel to each other. Two monomers are related by one NCS twofold axis and the other two are related by a second NCS twofold axis. Within each dimer, the primary interactions between monomers are hydrophobic.

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The active site of the TenI with bound cThz-P.

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Toms AV, Haas AL, Park J-H, Begley TP and Ealick SE. Structural Characterization of the Regulatory Proteins TenA and TenI from Bacillus subtilis and the identification of TenA as a Thiaminase II. Biochemistry 44:2319-2329 (2005).

*Hazra AB, Han Y, Chatterjee A, Zhang Y, Lai RY, Ealick SE, and Begley TP. A Missing Enzyme in Thiamin Thiazole Biosynthesis: Identification of TenI as a Thiazole Tautomerase. J. Am. Chem. Soc. (in press) (2011).

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