Steve Ealick's Research Group


Toxoflavin Lyase


PDB files:

*3PKV apoTflA

*3PKW holo TflA

*3PKX TflA complex with toxoflavin

Description:

Toxoflavin is an azapteridine that is toxic to various plants, fungi, animals, and bacteria.  This toxicity motivated the development of transgenic plants that degrade toxoflavin by expressing a gene tflA of Paenibacillus polymyxa JH. The metalloenzyme TflA, toxoflavin lyase, is structurally homologous to proteins of the vicinal oxygen chelate superfamily. 

TflA is an α/β protein formed from two domains each containing a seven-stranded mixed β-sheet. In turn each of the domains contain two modules. Within each domain, the modules are structurally similar to each other and are related by pseudotwofold symmetry.

 


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In the complex, toxoflavin interacts with residues from each of the four modules. The manganese binding site consists of a facial triad comprising residues His60, Glu113, and Glu138 (1-His-2-carboxylate). 


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References:

*Fenwick MK, Philmus B, Begley TP, and Ealick SE. Toxoflavin Lyase Requires a Novel 1-His-2-Carboxylate Facial Triad. Biochemistry 50:1091-1100 (2011). Abstract. PubMed

Philmus B, Abdelwahed S, Williams HJ, Fenwick MK, Ealick SE, and Begley TP. Identification of the product of Toxoflavin lyase: degradation via a Baeyer-Villiger oxidation. J. Am. Chem. Soc. 134:5326-5330. (2012). Abstract PubMed



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