1ax4

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spinqualitylabelsall models PDB ID 1ax4 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
, resolution 2.1Å
Sites:	, , , , , , and
Ligands:
Activity:	Tryptophanase, with EC number 4.1.99.1
Coordinates:	save as pdb, mmCIF, xml

TRYPTOPHANASE FROM PROTEUS VULGARIS

Overview

The X-ray structure of tryptophanase (Tnase) reveals the interactions responsible for binding of the pyridoxal 5'-phosphate (PLP) and atomic details of the K+ binding site essential for catalysis. The structure of holo Tnase from Proteus vulgaris (space group P2(1)2(1)2(1) with a = 115.0 A, b = 118.2 A, c = 153.7 A) has been determined at 2.1 A resolution by molecular replacement using tyrosine phenol-lyase (TPL) coordinates. The final model of Tnase, refined to an R-factor of 18.7%, (Rfree = 22.8%) suggests that the PLP-enzyme from observed in the structure is a ketoenamine. PLP is bound in a cleft formed by both the small and large domains of one subunit and the large domain of the adjacent subunit in the so-called "catalytic" dimer. The K+ cations are located on the interface of the subunits in the dimer. The structure of the catalytic dimer and mode of PLP binding in Tnase resemble those found in aspartate amino-transferase, TPL, omega-amino acid pyruvate aminotransferase, dialkylglycine decarboxylase (DGD), cystathionine beta-lyase and ornithine decarboxylase. No structural similarity has been detected between Tnase and the beta 2 dimer of tryptophan synthase which catalyses the same beta-replacement reaction. The single monovalent cation binding site of Tnase is similar to that of TPL, but differs from either of those in DGD.

About this Structure

1AX4 is a Single protein structure of sequence from Proteus vulgaris. Full crystallographic information is available from OCA.

Reference

Crystal structure of tryptophanase., Isupov MN, Antson AA, Dodson EJ, Dodson GG, Dementieva IS, Zakomirdina LN, Wilson KS, Dauter Z, Lebedev AA, Harutyunyan EH, J Mol Biol. 1998 Feb 27;276(3):603-23. PMID:9551100

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