1kl7
From Proteopedia
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Crystal Structure of Threonine Synthase from Yeast
Overview
Threonine synthase catalyzes the final step of threonine biosynthesis, the pyridoxal 5'-phosphate (PLP)-dependent conversion of O-phosphohomoserine into threonine and inorganic phosphate. Threonine is an essential nutrient for mammals, and its biosynthetic machinery is restricted to bacteria, plants, and fungi; therefore, threonine synthase represents an interesting pharmaceutical target. The crystal structure of threonine synthase from Saccharomyces cerevisiae has been solved at 2.7 A resolution using multiwavelength anomalous diffraction. The structure reveals a monomer as active unit, which is subdivided into three distinct domains: a small N-terminal domain, a PLP-binding domain that covalently anchors the cofactor and a so-called large domain, which contains the main of the protein body. All three domains show the typical open alpha/beta architecture. The cofactor is bound at the interface of all three domains, buried deeply within a wide canyon that penetrates the whole molecule. Based on structural alignments with related enzymes, an enzyme-substrate complex was modeled into the active site of yeast threonine synthase, which revealed essentials for substrate binding and catalysis. Furthermore, the comparison with related enzymes of the beta-family of PLP-dependent enzymes indicated structural determinants of the oligomeric state and thus rationalized for the first time how a PLP enzyme acts in monomeric form.
About this Structure
1KL7 is a Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Active as Threonine synthase, with EC number 4.2.3.1 Full crystallographic information is available from OCA.
Reference
Structure and function of threonine synthase from yeast., Garrido-Franco M, Ehlert S, Messerschmidt A, Marinkovic' S, Huber R, Laber B, Bourenkov GP, Clausen T, J Biol Chem. 2002 Apr 5;277(14):12396-405. Epub 2001 Dec 26. PMID:11756443
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