structures of the enzyme without acetate, the complex formed by the K127A mutant with the external Schiff base of pyridoxal 5'-phosphate with O-phosphoserine, and the complex formed by the K127A mutant with the external Schiff base of pyridoxal 5'-phosphate with O-acetylserine, to 2.1 A resolution. No significant difference is seen in the overall structure between the free and complexed forms of the enzyme. The side chains of T152, S153, and Q224 interact with the carboxylate of the substrate. The position of R297 is significantly unchanged in the complex of the K127A mutant with the external Schiff base, allowing enough space for an interaction with O-phosphoserine. The positively charged environment around the entrance of the active site including S153 and R297 is important for accepting negatively charged substrates
construction of a model of the cysteine synthase complex composed of the enzymes serine-acetyl-transferase SAT and O-acetyl-serine-(thiol)-lyase OAS-TL. Binding energy calculations suggest that, consistent with experiments, a ratio of two OAS-TL dimers to one SAT hexamer is likely
to elucidate the structural basis of proteinprotein interactions in the plant Cys synthase complex, the crystal structure of Arabidopsis thaliana O-acetylserine sulfhydrylase bound with a peptide corresponding to the C-terminal 10 residues of Arabidopsis serine acetyltransferase (C10 peptide) is determiend at 2.9 A resolution
native enzyme and mutant Q96A/Y125A, to 1.54 and 0.97 A resolution, respectively. OASS does not interact with its cognate serine acetyltransferase C-terminal tail. Crystal structures show that residues Gln96 and Tyr125 occupy the active-site pocket and interfere with the entry of the serine acetyltransferase C-terminal tail
analysis of the three-dimensional crystal structure of O-acetyl-L-serine sulfhydrylase enzyme complexed with cysteine and pyridoxal 5'-phosphate ligands, PDB ID 3BM5, determined by X-ray crystallography
hanging-drop vapour-diffusion method, crystals belong to the tetragonal space group P4(1), with unit cell parameters a = 80.3, b = 80.3, c = 112.2 A, two molecules per asymmetric unit and a complete data set is collected to a resolution of 1.86 A
native and in complex with its product L-cysteine, 50 mM Tris buffer, pH 8.0, with 150 mM NaCl, hanging drop method at 16°C, 2.3 M ammonium sulfate as precipitant for the complex with 5 mM cysteine in 100 mM Tris, pH 7.2, with increasing glycerol concentrations, diffraction data collection at -173°C
native protein at 1.86 A resolution, in complex with product cysteine at 2.4 A resolution. The dimeric interface lacks a chloride binding site. The N-terminal extension participates in dimeric interactions in a domain swapping manner. Sulfate is bound in the active site of the native structure, which is replaced by cysteine in the cysteine bound form
in complex with substrate analog citrate, at 1.33 A resolution. The C1-carboxylate of citrate is bound at the carboxylate position of O-acetylserine, whereas the C6-carboxylate adopts two conformations. Modeling of the unnatural substrate 5-thio-2-nitrobenzoate into the structure
complex with inhibitory pentapeptides MNYDI (10 mM HEPES, pH 8.0, 25 mM NaCl, 8.8 mM peptide), MNKGI (20 mM HEPES, pH 7.5, 20 mM NaCl, 12.5 mM peptide), MNWNI (10 mM HEPES, pH 7.5, 25 mM NaCl, 7.5 mM peptide), MNYFI (20 mM HEPES, pH 8.0, 20 mM NaCl, 12.7 mM peptide), MNENI (10 mM HEPES, pH 7.5, 25 mM NaCl, 9.4 mM peptide), and MNETI (20 mM HEPES, pH 7.5, 20 mM NaCl, 9.4 mM peptide), reservoir solution is 100 mM HEPES, pH 7.5, between 1.8 and 2.1 M (NH4)2SO4, and polyethylene glycol 400, except for the complex with MNWNI (100 mM CAPS, pH 10.5, 1.75 (NH4)2SO4, and 0.2 M Li2SO4), the cryoprotection solution contains glycerol, hanging drop vapor diffusion method, diffraction data are measured at -183°C
to 1.8 A resolution. The biologically active unit, a dimer, constitutes the asymmetric unit. Subunit A contains residues 3-213 and 241-333, whilst subunit B comprises residues 4-214 and 241-333. A surface loop from residues 214 to 241 is disordered. The subunit contains two domains. The smaller domain I is constructed by residues 51-158, which primarily form a four-stranded beta-sheet surrounded by four alpha-helices. The larger domain II comprises residues 21-50 and 159-306. Domain II contains four alpha-helices and six beta-strands which, together with a beta-strand contributed from the partner-subunit domain I, form a seven-membered beta-sheet. In addition, residues 307-333 at the C-terminus form an extended helix-loop-helix structure that stretches across the surface of the partner subunit
purified isozyme CysK1, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 0.1 M MOPS, pH 6.0, 60% 2-methyl-2,4-pentanediol, 16°C, X-ray diffraction structure determination and analysis at 2.30 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model
purified isozyme CysK2 in complex with cystine, hanging drop vapor diffusion technique, mixing of 10 mg/ml protein solution with an equal volume of reservoir solution containing 1.5 M (NH4)2SO4, 0.1M Bis-Tris-propane, pH 7.0, and 10 mM cystine, 16°C, X-ray diffraction structure determination and analysis at 1.91 A resolution, molecular replacement using the coordinates of Mycobacterium tuberculosis OASS, PDB ID 2Q3B, as the search model
trapping of the alpha-aminoacrylate reaction intermediate and determination of its structure by cryocrystallography, 2.2 A resolution. Determination of the crystal structure of the enzyme bound to an inhibitory four-residue peptide derived from the C-terminus of Mycobacterium tuberculosis CysE (SAT, Rv2335). The structure of this inhibited form of CysK1 may provide the basis for the design of strong binding inhibitors of this enzyme
wild-type and mutant K43A, to 2.25 and 1.9 A resolution, respectively. Each monomer of DcsD takes a typical fold of type II pyridoxal 5'-phosphate enzymes with the cofactor pyridoxal 5'-phosphate covalently bound to invariant Lys residue (Lys43) at the active site. The pyridine ring of pyridoxal 5'-phoshate makes hydrogen bonds with invariant Asn73 and Ser265 residues. Its phosphate group makes hydrogen bonds with Gly177, Thr178, Thr179 and Thr181 residues