6dmk
From Proteopedia
A multiconformer ligand model of an isoxazolyl-benzimidazole ligand bound to the bromodomain of human CREBBP
Structural highlights
Disease[CBP_HUMAN] Note=Chromosomal aberrations involving CREBBP may be a cause of acute myeloid leukemias. Translocation t(8;16)(p11;p13) with KAT6A; translocation t(11;16)(q23;p13.3) with MLL/HRX; translocation t(10;16)(q22;p13) with KAT6B. KAT6A-CREBBP may induce leukemia by inhibiting RUNX1-mediated transcription. Defects in CREBBP are a cause of Rubinstein-Taybi syndrome type 1 (RSTS1) [MIM:180849]. RSTS1 is an autosomal dominant disorder characterized by craniofacial abnormalities, broad thumbs, broad big toes, mental retardation and a propensity for development of malignancies.[1] [2] [3] [4] Function[CBP_HUMAN] Acetylates histones, giving a specific tag for transcriptional activation. Also acetylates non-histone proteins, like NCOA3 and FOXO1. Binds specifically to phosphorylated CREB and enhances its transcriptional activity toward cAMP-responsive genes. Acts as a coactivator of ALX1 in the presence of EP300.[5] [6] [7] [8] Publication Abstract from PubMedProteins and ligands sample a conformational ensemble that governs molecular recognition, activity, and dissociation. In structure-based drug design, access to this conformational ensemble is critical to understand the balance between entropy and enthalpy in lead optimization. However, ligand conformational heterogeneity is currently severely underreported in crystal structures in the Protein Data Bank, owing in part to a lack of automated and unbiased procedures to model an ensemble of protein-ligand states into X-ray data. Here, we designed a computational method, qFit-ligand, to automatically resolve conformationally averaged ligand heterogeneity in crystal structures, and applied it to a large set of protein receptor-ligand complexes. In an analysis of the cancer related BRD4 domain, we found that up to 29% of protein crystal structures bound with drug-like molecules present evidence of unmodeled, averaged, relatively iso-energetic conformations in ligand-receptor interactions. In many retrospective cases, these alternate conformations were adventitiously exploited to guide compound design, resulting in improved potency or selectivity. Combining qFit-ligand with high-throughput screening or multi-temperature crystallography could therefore augment the structure-based drug design toolbox. qFit-ligand reveals widespread conformational heterogeneity of drug-like molecules in X-ray electron density maps.,van Zundert G, Hudson BM, de Oliveira S, Keedy DA, Fonseca R, Heliou A, Suresh P, Borrelli K, Day T, Fraser J, van den Bedem H J Med Chem. 2018 Nov 20. doi: 10.1021/acs.jmedchem.8b01292. PMID:30457858[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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