2inx

Crystal Structure of Ketosteroid Isomerase D40N from Pseudomonas putida (pKSI) with bound 2,6-difluorophenol

spinqualitylabelsall models 2inx, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2inx is a 1 chain structure with sequence from Pseudomonas putida. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FFP Gene: ksi (Pseudomonas putida) Activity: Steroid Delta-isomerase, with EC number 5.3.3.1 Resources: FirstGlance, OCA, RCSB, PDBsum 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 Enzymes are classically proposed to accelerate reactions by binding substrates within active-site environments that are structurally preorganized to optimize binding interactions with reaction transition states rather than ground states. This is a remarkably formidable task considering the limited 0.1-1 A scale of most substrate rearrangements. The flexibility of active-site functional groups along the coordinate of substrate rearrangement, the distance scale on which enzymes can distinguish structural rearrangement, and the energetic significance of discrimination on that scale remain open questions that are fundamental to a basic physical understanding of enzyme active sites and catalysis. We bring together 1.2-1.5 A resolution X-ray crystallography, (1)H and (19)F NMR spectroscopy, quantum mechanical calculations, and transition-state analogue binding measurements to test the distance scale on which noncovalent forces can constrain the structural relaxation or translation of side chains and ligands along a specific coordinate and the energetic consequences of such geometric constraints within the active site of bacterial ketosteroid isomerase (KSI). Our results strongly suggest that packing and binding interactions within the KSI active site can constrain local side-chain reorientation and prevent hydrogen bond shortening by 0.1 A or less. Further, this constraint has substantial energetic effects on ligand binding and stabilization of negative charge within the oxyanion hole. These results provide evidence that subtle geometric effects, indistinguishable in most X-ray crystallographic structures, can have significant energetic consequences and highlight the importance of using synergistic experimental approaches to dissect enzyme function. Testing geometrical discrimination within an enzyme active site: constrained hydrogen bonding in the ketosteroid isomerase oxyanion hole.,Sigala PA, Kraut DA, Caaveiro JM, Pybus B, Ruben EA, Ringe D, Petsko GA, Herschlag D J Am Chem Soc. 2008 Oct 15;130(41):13696-708. Epub 2008 Sep 23. PMID:18808119 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ketosteroid Isomerase

Proteopedia Page Contributors and Editors (what is this?)

OCA