2OQX

Crystal Structure of the apo form of E. coli tryptophanase at 1.9 A resolution

Summary for 2OQX

• Entry DOI: 10.2210/pdb2oqx/pdb
• Related: 1AX4 1TPL 2C44
• Descriptor: Tryptophanase, CHLORIDE ION, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: lyase, pyridoxal phosphate, tryptophan catabolism
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 52762.99

Authors

Goldgur, Y.,Kogan, A.,Gdalevsky, G.,Parola, A.,Cohen-Luria, R.,Almog, O. (deposition date: 2007-02-01, release date: 2007-02-20, Last modification date: 2024-10-30)

Primary citation

Tsesin, N.,Kogan, A.,Gdalevsky, G.Y.,Himanen, J.P.,Cohen-Luria, R.,Parola, A.H.,Goldgur, Y.,Almog, O.
The structure of apo tryptophanase from Escherichia coli reveals a wide-open conformation.
Acta Crystallogr.,Sect.D, 63:969-974, 2007

PubMed Abstract: The crystal structure of apo tryptophanase from Escherichia coli (space group F222, unit-cell parameters a = 118.4, b = 120.1, c = 171.2 A) was determined at 1.9 A resolution using the molecular-replacement method and refined to an R factor of 20.3% (R(free) = 23.2%). The structure revealed a significant shift in the relative orientation of the domains compared with both the holo form of Proteus vulgaris tryptophanase and with another crystal structure of apo E. coli tryptophanase, reflecting the internal flexibility of the molecule. Domain shifts were previously observed in tryptophanase and in the closely related enzyme tyrosine phenol-lyase, with the holo form found in an open conformation and the apo form in either an open or a closed conformation. Here, a wide-open conformation of the apo form of tryptophanase is reported. A conformational change is also observed in loop 297-303. The structure contains a hydrated Mg(2+) at the cation-binding site and a Cl(-) ion at the subunit interface. The enzyme activity depends on the nature of the bound cation, with smaller ions serving as inhibitors. It is hypothesized that this effect arises from variations of the coordination geometry of the bound cation.

PubMed: 17704565
DOI: 10.1107/S0907444907036396

Experimental method

X-RAY DIFFRACTION (1.9 Å)