8i7l

Crystal structure of indoleamine 2,3-dioxygenagse 1 (IDO1) complexed with a novel inhibitor

spinqualitylabelsall models 8i7l, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8i7l is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Ligands: OIH, THJ Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function I23O1_HUMAN Catalyzes the cleavage of the pyrrol ring of tryptophan and incorporates both atoms of a molecule of oxygen. Publication Abstract from PubMed The pharmacological inhibition of IDO1 is considered an effective therapeutic approach for cancer treatment. However, the inadequate response of existing holo-IDO1 inhibitors and unclear biomarkers available in clinical practice limit the possibility of developing efficacious IDO1 inhibitors. In the current study, we aimed to elucidate the activity and mechanism of a potent 1H-pyrrole-2-carboxylic acid derivative (B37) targeting apo-IDO1 and to determine its role in tumor therapy. By competing with heme for binding to apo-IDO1, B37 potently inhibited IDO1 activity, with an IC(50) of 22 pM assessed using a HeLa cell-based assay. The x-ray cocrystal structure of the inhibitor-enzyme complex showed that the B37-human IDO1 complex has strong hydrophobic interactions, which enhances its binding affinity, determined using isothermal titration calorimetry. Stronger noncovalent interactions, including pi stacking and hydrogen bonds formed between B37 and apo-human IDO1, underlay the enthalpy-driven force for B37 for binding to the enzyme. These binding properties endowed B37 with potent antitumor efficacy, which was confirmed in a mouse colon cancer CT26 syngeneic model in BALB/c mice and in an azoxymethane/dextran sulfate sodium-induced colon carcinogenesis model in C57BL/6 mice by activating the host immune system. Moreover, the combination of B37 and anti-PD1 Ab synergistically inhibited tumor growth. These results suggested that B37 may serve as a unique candidate for apo-IDO1 inhibition-mediated tumor immunotherapy. Apo-Form Selective Inhibition of IDO for Tumor Immunotherapy.,Liu W, Zou Y, Li K, Zhong H, Yu L, Ge S, Lai Y, Dong X, Xu Q, Guo W J Immunol. 2022 Jul 1;209(1):180-191. doi: 10.4049/jimmunol.2100938. Epub 2022 , Jun 20. PMID:35725271 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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