1ax4: Difference between revisions
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==Overview== | ==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 ... | 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== | ==About this Structure== | ||
1AX4 is a | 1AX4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Proteus_vulgaris Proteus vulgaris] with K as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Tryptophanase Tryptophanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.99.1 4.1.99.1] Structure known Active Sites: LPA, LPB, LPC, LPD, POA, POB, POC and POD. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1AX4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: tryptophan indole-lyase]] | [[Category: tryptophan indole-lyase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:39:53 2007'' | ||
