Ligandability Assessment of IL-1β by Integrated Hit Identification Approaches.

Human interleukin-1β (IL-1β) is a pro-inflammatory cytokine that plays a critical role in the regulation of the immune response and the development of various inflammatory diseases. In this publication, we disclose our efforts toward the discovery of IL-1β binders that interfere with IL-1β signaling. To this end, several technologies were used in parallel, including fragment-based screening (FBS), DNA-encoded library (DEL) technology, peptide discovery platform (PDP), and virtual screening.

Discovery of a selective and biologically active low-molecular weight antagonist of human interleukin-1β.

Human interleukin-1β (hIL-1β) is a pro-inflammatory cytokine involved in many diseases. While hIL-1β directed antibodies have shown clinical benefit, an orally available low-molecular weight antagonist is still elusive, limiting the applications of hIL-1β-directed therapies. Here we describe the discovery of a low-molecular weight hIL-1β antagonist that blocks the interaction with the IL-1R1 receptor.

Structure-Based Design and Preclinical Characterization of Selective and Orally Bioavailable Factor XIa Inhibitors: Demonstrating the Power of an Integrated S1 Protease Family Approach.

The serine protease factor XI (FXI) is a prominent drug target as it holds promise to deliver efficacious anticoagulation without an enhanced risk of major bleeds. Several efforts have been described targeting the active form of the enzyme, FXIa. Herein, we disclose our efforts to identify potent, selective, and orally bioavailable inhibitors of FXIa.

Discovery of 4-((2,4)-4-Ethoxy-1-((5-methoxy-7-methyl-1-indol-4-yl)methyl)piperidin-2-yl)benzoic Acid (LNP023), a Factor B Inhibitor Specifically Designed To Be Applicable to Treating a Diverse Array of Complement Mediated Diseases.

The alternative pathway (AP) of the complement system is a key contributor to the pathogenesis of several human diseases including age-related macular degeneration, paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and various glomerular diseases. The serine protease factor B (FB) is a key node in the AP and is integral to the formation of C3 and C5 convertase. Despite the prominent role of FB in the AP, selective orally bioavailable inhibitors, beyond our own efforts, have not been reported previously.

Structure-Guided Design of Substituted Biphenyl Butanoic Acid Derivatives as Neprilysin Inhibitors.

Inhibition of neprilysin (NEP) is widely studied as a therapeutic target for the treatment of hypertension, heart failure, and kidney disease. Sacubitril/valsartan (LCZ696) is a drug approved to reduce the risk of cardiovascular death in heart failure patients with reduced ejection fraction. LBQ657 is the active metabolite of sacubitril and an inhibitor of NEP.

MAA868, a novel FXI antibody with a unique binding mode, shows durable effects on markers of anticoagulation in humans.

A large unmet medical need exists for safer antithrombotic drugs because all currently approved anticoagulant agents interfere with hemostasis, leading to an increased risk of bleeding. Genetic and pharmacologic evidence in humans and animals suggests that reducing factor XI (FXI) levels has the potential to effectively prevent and treat thrombosis with a minimal risk of bleeding. We generated a fully human antibody (MAA868) that binds the catalytic domain of both FXI (zymogen) and activated FXI.

Structure of neprilysin in complex with the active metabolite of sacubitril.

Sacubitril is an ethyl ester prodrug of LBQ657, the active neprilysin (NEP) inhibitor, and a component of LCZ696 (sacubitril/valsartan). We report herein the three-dimensional structure of LBQ657 in complex with human NEP at 2 Å resolution. The crystal structure unravels the binding mode of the compound occupying the S1, S1' and S2' sub-pockets of the active site, consistent with a competitive inhibition mode.

The molecular mode of action and species specificity of canakinumab, a human monoclonal antibody neutralizing IL-1β.

Interleukin-1β (IL-1β) plays a key role in autoinflammatory diseases, such as systemic juvenile idiopathic arthritis (sJIA) or cryopyrin-associated periodic syndrome (CAPS). Canakinumab, a human monoclonal anti-IL-1β antibody, was recently approved for human use under the brand name Ilaris®. Canakinumab does not cross-react with IL-1β from mouse, rat, rabbit, or macaques.

Structure-based design and optimization of potent inhibitors of the adenoviral protease.

Adenoviral infections are associated with a wide range of acute diseases, among which ocular viral conjunctivitis (EKC) and disseminated disease in immunocompromised patients. To date, no approved specific anti-adenoviral drug is available, but there is a growing need for an effective treatment of such infections. The adenoviral protease, adenain, plays a crucial role for the viral lifecycle and thus represents an attractive therapeutic target.

Discovery and structure-based optimization of adenain inhibitors.

The cysteine protease adenain is the essential protease of adenovirus and, as such, represents a promising target for the treatment of ocular and other adenoviral infections. Through a concise two-pronged hit discovery approach we identified tetrapeptide nitrile 1 and pyrimidine nitrile 2 as complementary starting points for adenain inhibition. These hits enabled the first high-resolution X-ray cocrystal structures of adenain with inhibitors bound and revealed the binding mode of 1 and 2.

Crystal Structures of Human MdmX (HdmX) in Complex with p53 Peptide Analogues Reveal Surprising Conformational Changes.

p53 tumor suppressor activity is negatively regulated through binding to the oncogenic proteins Hdm2 and HdmX. The p53 residues Leu(26), Trp(23), and Phe(19) are crucial to mediate these interactions. Inhibiting p53 binding to both Hdm2 and HdmX should be a promising clinical approach to reactivate p53 in the cancer setting, but previous studies have suggested that the discovery of dual Hdm2/HdmX inhibitors will be difficult.

Affinity classification of kinase inhibitors by mass spectrometric methods and validation using standard IC(50) measurements.

Protein kinases have emerged as a major drug target in the last years. Since more than 500 kinases are encoded in the human genome, cross-reactivity of a majority of kinase inhibitors causes problems. Tools are required for a rapid classification of inhibitors according to their affinity for a certain target to refine the search for new, more specific lead compounds.

Chaperone over-expression in Escherichia coli: apparent increased yields of soluble recombinant protein kinases are due mainly to soluble aggregates.

The recombinant expression of eukaryotic proteins in Escherichia coli often results in protein aggregation. Several articles report on improved solubility and increased purification yields of individual proteins upon over-expression of E. coli chaperones but this effect might potentially be protein-specific.

Structural basis of guanine nucleotide exchange mediated by the T-cell essential Vav1.

The guanine nucleotide exchange factor (GEF) Vav1 plays an important role in T-cell activation and tumorigenesis. In the GEF superfamily, Vav1 has the ability to interact with multiple families of Rho GTPases. The structure of the Vav1 DH-PH-CRD/Rac1 complex to 2.

NMR-Based Strategies to Elucidate Bioactive Conformations of Weakly Binding Ligands.

Key processes in molecular biology are regulated by interactions between biomolecules. Protein-proteinand protein-ligand interactions, e.g.

Remedial strategies in structural proteomics: expression, purification, and crystallization of the Vav1/Rac1 complex.

The signal transduction pathway involving the Vav1 guanine nucleotide exchange factor (GEF) and the Rac1 GTPase plays several key roles in the immune response mediated by the T cell receptor. Vav1 is also a unique member of the GEF family in that it contains a cysteine-rich domain (CRD) that is critical for Rac1 binding and maximal guanine nucleotide exchange activity, and thus may provide a unique protein-protein interface compared to other GEF/GTPase pairs. Here, we have applied a number of remedial structural proteomics strategies, such as construct and expression optimization, surface mutagenesis, limited proteolysis, and protein formulation to successfully express, purify, and crystallize the Vav1-DH-PH-CRD/Rac1 complex in an active conformation.

Structural basis for the exceptional in vivo efficacy of bisphosphonate drugs.

To understand the structural basis for bisphosphonate therapy of bone diseases, we solved the crystal structures of human farnesyl pyrophosphate synthase (FPPS) in its unliganded state, in complex with the nitrogen-containing bisphosphonate (N-BP) drugs zoledronate, pamidronate, alendronate, and ibandronate, and in the ternary complex with zoledronate and the substrate isopentenyl pyrophosphate (IPP). By revealing three structural snapshots of the enzyme catalytic cycle, each associated with a distinct conformational state, and details about the interactions with N-BPs, these structures provide a novel understanding of the mechanism of FPPS catalysis and inhibition. In particular, the accumulating substrate, IPP, was found to bind to and stabilize the FPPS-N-BP complexes rather than to compete with and displace the N-BP inhibitor.

Structure-based design, synthesis, and memapsin 2 (BACE) inhibitory activity of carbocyclic and heterocyclic peptidomimetics.

Molecular modeling based on the X-ray crystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM99-2) of BACE led to the design and synthesis of a series of constrained P(1)' analogues. A cyclopentane ring was incorporated in 1 spanning the P(1)' Ala methyl group and the adjacent methylene carbon atom of the chain. Progressive truncation at the P(2)'-P(4)' sites led to a potent truncated analogue 5 with good selectivity over Cathepsin D.

Selective estrogen receptor modulators with conformationally restricted side chains. Synthesis and structure-activity relationship of ERalpha-selective tetrahydroisoquinoline ligands.

We disclose herein the discovery of estrogen receptor alpha (ERalpha) selective estrogen receptor modulators (SERMs) of the tetrahydroisoquinoline series that incorporate novel conformationally restricted side chains as replacement of the aminoethoxy residue typical of SERMs. Molecular modeling studies used in conjunction with the X-ray crystal structure of the ERalpha ligand binding domain (LBD) with raloxifene (7) suggested a diazadecaline moiety as a viable mimic of the SERM side chain. On the basis of this knowledge, the piperidinylethoxy moiety of our lead compound 60 was replaced by a diazadecaline subunit, providing the novel tetrahydroisoquinoline 29.

The likelihood of aggregation during protein renaturation can be assessed using the second virial coefficient.

Protein aggregation is commonly observed during protein refolding. To better understand this phenomenon, the intermolecular interactions experienced by a protein during unfolding and refolding are inferred from second virial coefficient (SVC) measurements. It is accepted that a negative SVC is indicative of protein-protein interactions that are attractive, whereas a positive SVC indicates net repulsive interactions.