1fs6
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(New page: 200px<br /><applet load="1fs6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1fs6, resolution 2.20Å" /> '''GLUCOSAMINE-6-PHOSPH...)
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Revision as of 13:06, 20 November 2007
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GLUCOSAMINE-6-PHOSPHATE DEAMINASE FROM E.COLI, T CONFORMER, AT 2.2A RESOLUTION
Overview
A new crystallographic structure of the free active-site R conformer of, the allosteric enzyme glucosamine-6-phosphate deaminase from Escherichia, coli, coupled with previously reported structures of the T and R, conformers, generates a detailed description of the heterotropic, allosteric transition in which structural flexibility plays a central, role. The T conformer's external zone [Horjales et al. (1999), Structure, 7, 527-536] presents higher B values than in the R conformers. The, ligand-free enzyme (T conformer) undergoes an allosteric transition to the, free active-site R conformer upon binding of the allosteric activator., This structure shows three alternate conformations of the mobile section, of the active-site lid (residues 163-182), in comparison to the high B, values for the unique conformation of the T conformer. One of these, alternate R conformations corresponds to the active-site lid found when, the substrate is bound. The disorder associated with the three alternate, conformations can be related to the biological regulation of the K(m) of, the enzyme for the reaction, which is metabolically required to maintain, adequate concentrations of the activator, which holds the enzyme in its R, state. Seven alternate conformations for the active-site lid and three for, the C-terminus were refined for the T structure using isotropic B factors., Some of these conformers approach that of the R conformer in geometry., Furthermore, the direction of the atomic vibrations obtained with, anisotropic B refinement supports the hypothesis of an oscillating rather, than a tense T state. The concerted character of the allosteric transition, is also analysed in view of the apparent dynamics of the conformers.
About this Structure
1FS6 is a Single protein structure of sequence from Escherichia coli. Active as Glucosamine-6-phosphate deaminase, with EC number 3.5.99.6 Full crystallographic information is available from OCA.
Reference
Structural flexibility, an essential component of the allosteric activation in Escherichia coli glucosamine-6-phosphate deaminase., Rudino-Pinera E, Morales-Arrieta S, Rojas-Trejo SP, Horjales E, Acta Crystallogr D Biol Crystallogr. 2002 Jan;58(Pt 1):10-20. Epub 2001, Dec 21. PMID:11752775
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