1ixe

Crystal structure of citrate synthase from Thermus thermophilus HB8

spinqualitylabelsall models 1ixe, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ixe is a 4 chain structure with sequence from Thermus thermophilus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3Å Ligands: CIT, COA, GOL, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, TOPSAN Function Q5SIM6_THET8 Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The crystal structures of citrate synthase from the thermophilic eubacteria Thermus thermophilus HB8 (TtCS) were determined for an open form at 1.5 A resolution and for closed form at 2.3 A resolution, respectively. In the absence of ligands TtCS in the open form was crystalized into a tetragonal form with a single subunit in the asymmetric unit. TtCS was also co-crystallized with citrate and coenzyme-A to form an orthorhombic crystal with two homodimers in the asymmetric unit. Citrate and CoA are found in the active site situated between the large domain and the small domain in all subunit whereas the complex shows two distinct closed conformations, the fully closed form and partially closed form. Structural comparisons are performed to describe conformational changes associated with binding of products of TtCS. Upon binding of citrate, basic residues in the active site move toward citrate and make a hydrogen bond network in the active site, inducing a large-scale rotation of the small domain relative to the large domain. CoA is sandwiched between the small and large domains and then the cysteamine tail is inserted into the active site with a cooperative rotation around mainchain dihedrals in the hinge region connecting helices M and N. According to this rotation these helices are extended to close the active site completely. The considerable flexibility and structural rearrangements in the hinge region are crucial for an ordered bibi reaction in catalysis for microbial CSs. Structural comparison between the open and closed forms of citrate synthase from Thermus thermophilus HB8.,Kanamori E, Kawaguchi S, Kuramitsu S, Kouyama T, Murakami M Biophys Physicobiol. 2015 Oct 10;12:47-56. doi: 10.2142/biophysico.12.0_47., eCollection 2015. PMID:27493854 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Citrate Synthase 3D structures

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