1i7q
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(New page: 200px<br /><applet load="1i7q" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i7q, resolution 1.95Å" /> '''ANTHRANILATE SYNTHAS...)
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Revision as of 15:00, 20 November 2007
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ANTHRANILATE SYNTHASE FROM S. MARCESCENS
Overview
The crystal structure of anthranilate synthase (AS) from Serratia, marcescens, a mesophilic bacterium, has been solved in the presence of its, substrates, chorismate and glutamine, and one product, glutamate, at 1.95, A, and with its bound feedback inhibitor, tryptophan, at 2.4 A. In, comparison with the AS structure from the hyperthermophile Sulfolobus, solfataricus, the S. marcescens structure shows similar subunit structures, but a markedly different oligomeric organization. One crystal form of the, S. marcescens enzyme displays a bound pyruvate as well as a putative, anthranilate (the nitrogen group is ambiguous) in the TrpE subunit. It, also confirms the presence of a covalently bound glutamyl thioester, intermediate in the TrpG subunit. The tryptophan-bound form reveals that, the inhibitor binds at a site distinct from that of the substrate, chorismate. Bound tryptophan appears to prevent chorismate binding by a, demonstrable conformational effect, and the structure reveals how, occupancy of only one of the two feedback inhibition sites can immobilize, the catalytic activity of both TrpE subunits. The presence of effectors in, the structure provides a view of the locations of some of the amino acid, residues in the active sites. Our findings are discussed in terms of the, previously described AS structure of S. solfataricus, mutational data, obtained from enteric bacteria, and the enzyme's mechanism of action.
About this Structure
1I7Q is a Protein complex structure of sequences from Serratia marcescens with MG, ILG, BEZ and PYR as ligands. Active as Anthranilate synthase, with EC number 4.1.3.27 Full crystallographic information is available from OCA.
Reference
The structures of anthranilate synthase of Serratia marcescens crystallized in the presence of (i) its substrates, chorismate and glutamine, and a product, glutamate, and (ii) its end-product inhibitor, L-tryptophan., Spraggon G, Kim C, Nguyen-Huu X, Yee MC, Yanofsky C, Mills SE, Proc Natl Acad Sci U S A. 2001 May 22;98(11):6021-6. PMID:11371633
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