1tdj
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(New page: 200px<br /><applet load="1tdj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tdj, resolution 2.8Å" /> '''THREONINE DEAMINASE (...)
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Revision as of 01:03, 21 November 2007
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THREONINE DEAMINASE (BIOSYNTHETIC) FROM E. COLI
Overview
BACKGROUND: Feedback inhibition of biosynthetic threonine deaminase (TD), from Escherichia coli provided one of the earliest examples of, protein-based metabolic regulation. Isoleucine, the pathway end-product, and valine, the product of a parallel pathway, serve as allosteric, inhibitor and activator, respectively. This enzyme is thus a useful model, system for studying the structural basis of allosteric control mechanisms., RESULTS: We report the crystal structure of TD at 2.8 A resolution. The, tetramer has 222 symmetry, with C-terminal regulatory domains projecting, out from a core of catalytic PLP-containing N-terminal domains. The, subunits, and especially the regulatory domains, associate extensively to, form dimers, which associate less extensively to form the tetramer. Within, the dimer, each monomer twists approximately 150 degrees around a thin, neck between the domains to place its catalytic domain adjacent to the, regulatory domain of the other subunit. CONCLUSIONS: The structure of TD, and its comparison with related structures and other data lead to the, tentative identification of the regulatory binding site and revealed, several implications for the allosteric mechanism. This work prepares the, way for detailed structure/function studies of the complex allosteric, behaviour of this enzyme.
About this Structure
1TDJ is a Single protein structure of sequence from Escherichia coli with PLP as ligand. Active as Threonine ammonia-lyase, with EC number 4.3.1.19 Full crystallographic information is available from OCA.
Reference
Structure and control of pyridoxal phosphate dependent allosteric threonine deaminase., Gallagher DT, Gilliland GL, Xiao G, Zondlo J, Fisher KE, Chinchilla D, Eisenstein E, Structure. 1998 Apr 15;6(4):465-75. PMID:9562556
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