Introduction of a Crystalline, Shelf-Stable Reagent for the Synthesis of Sulfur(VI) Fluorides.

The design, synthesis, and application of [4-(acetylamino)phenyl]imidodisulfuryl difluoride (AISF), a shelf-stable, crystalline reagent for the synthesis of sulfur(VI) fluorides, is described. The utility of AISF is demonstrated in the synthesis of a diverse array of aryl fluorosulfates and sulfamoyl fluorides under mild conditions. Additionally, a single-step preparation of AISF was developed that installed the bis(fluorosulfonyl)imide group on acetanilide utilizing an oxidative C-H functionalization protocol.

Lysosomal integral membrane protein-2 as a phospholipid receptor revealed by biophysical and cellular studies.

Lysosomal integral membrane protein-2 (LIMP-2/SCARB2) contributes to endosomal and lysosomal function. LIMP-2 deficiency is associated with neurological abnormalities and kidney failure and, as an acid glucocerebrosidase receptor, impacts Gaucher and Parkinson's diseases. Here we report a crystal structure of a LIMP-2 luminal domain dimer with bound cholesterol and phosphatidylcholine.

Development of a high-throughput crystal structure-determination platform for JAK1 using a novel metal-chelator soaking system.

Crystals of phosphorylated JAK1 kinase domain were initially generated in complex with nucleotide (ADP) and magnesium. The tightly bound Mg-ADP at the ATP-binding site proved recalcitrant to ligand displacement. Addition of a molar excess of EDTA helped to dislodge the divalent metal ion, promoting the release of ADP and allowing facile exchange with ATP-competitive small-molecule ligands.

Binding site elucidation and structure guided design of macrocyclic IL-17A antagonists.

Interleukin-17A (IL-17A) is a principal driver of multiple inflammatory and immune disorders. Antibodies that neutralize IL-17A or its receptor (IL-17RA) deliver efficacy in autoimmune diseases, but no small-molecule IL-17A antagonists have yet progressed into clinical trials. Investigation of a series of linear peptide ligands to IL-17A and characterization of their binding site has enabled the design of novel macrocyclic ligands that are themselves potent IL-17A antagonists.

Probing the enzyme kinetics, allosteric modulation and activation of α1- and α2-subunit-containing AMP-activated protein kinase (AMPK) heterotrimeric complexes by pharmacological and physiological activators.

AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that serves as a pleotropic regulator of whole body energy homoeostasis. AMPK exists as a heterotrimeric complex, composed of a catalytic subunit (α) and two regulatory subunits (β and γ), each present as multiple isoforms. In the present study, we compared the enzyme kinetics and allosteric modulation of six recombinant AMPK isoforms, α1β1γ1, α1β2γ1, α1β2γ3, α2β1γ1, α2β2γ1 and α2β2γ3 using known activators, A769662 and AMP.

Expression and functional characterization of human lysosomal acid lipase gene (LIPA) mutation responsible for cholesteryl ester storage disease (CESD) phenotype.

Lysosomal acid lipase (LAL) is a serine hydrolase which hydrolyzes cholesteryl ester and triglycerides delivered to the lysosomes into free cholesterol and free fatty acids. Mutations in the LAL gene (LIPA) result in accumulation of triglycerides and cholesterol esters in various tissues of the body, leading to pathological conditions such as Wolman's disease (WD) and cholesteryl ester storage disease (CESD). CESD patients homozygous for His295Tyr (H295Y) mutation have less than 5% of normal LAL activity.

Structural basis for AMPK activation: natural and synthetic ligands regulate kinase activity from opposite poles by different molecular mechanisms.

AMP-activated protein kinase (AMPK) is a principal metabolic regulator affecting growth and response to cellular stress. Comprised of catalytic and regulatory subunits, each present in multiple forms, AMPK is best described as a family of related enzymes. In recent years, AMPK has emerged as a desirable target for modulation of numerous diseases, yet clinical therapies remain elusive.

A potentiator of orthosteric ligand activity at GLP-1R acts via covalent modification.

We report that 4-(3-(benzyloxy)phenyl)-2-ethylsulfinyl-6-(trifluoromethyl)pyrimidine (BETP), which behaves as a positive allosteric modulator at the glucagon-like peptide-1 receptor (GLP-1R), covalently modifies cysteines 347 and 438 in GLP-1R. C347, located in intracellular loop 3 of GLP-1R, is critical to the activity of BETP and a structurally distinct GLP-1R ago-allosteric modulator, N-(tert-butyl)-6,7-dichloro-3-(methylsulfonyl)quinoxalin-2-amine. We further show that substitution of cysteine for phenylalanine 345 in the glucagon receptor is sufficient to confer sensitivity to BETP.

Activation of AMP-activated protein kinase revealed by hydrogen/deuterium exchange mass spectrometry.

AMP-activated protein kinase (AMPK) monitors cellular energy, regulates genes involved in ATP synthesis and consumption, and is allosterically activated by nucleotides and synthetic ligands. Analysis of the intact enzyme with hydrogen/deuterium exchange mass spectrometry reveals conformational perturbations of AMPK in response to binding of nucleotides, cyclodextrin, and a synthetic small molecule activator, A769662. Results from this analysis clearly show that binding of AMP leads to conformational changes primarily in the γ subunit of AMPK and subtle changes in the α and β subunits.

Crystal structures of interleukin 17A and its complex with IL-17 receptor A.

The constituent polypeptides of the interleukin-17 family form six different homodimeric cytokines (IL-17A-F) and the heterodimeric IL-17A/F. Their interactions with IL-17 receptors A-E (IL-17RA-E) mediate host defenses while also contributing to inflammatory and autoimmune responses. IL-17A and IL-17F both preferentially engage a receptor complex containing one molecule of IL-17RA and one molecule of IL-17RC.

Unexpected mucin-type O-glycosylation and host-specific N-glycosylation of human recombinant interleukin-17A expressed in a human kidney cell line.

The T helper cell-derived cytokine interleukin-17A (IL-17A) is a variably glycosylated disulfide-linked homodimer of 34-38 kDa. Its polypeptide monomer contains one canonical N-glycosylation site at Asn68, and human recombinant IL-17A was partly N-glycosylated when expressed in human kidney (HEK293) cells as a fusion protein with a melittin signal sequence and an N-terminal hexahistidine tag. Orbitrap mass analyses of the tryptic N-glycopeptide 63-69 indicated that the N-glycosylation was of the GalNAc-terminated type characteristic of cultured kidney cells.

Escherichia coli expression, purification and characterization of functional full-length recombinant alpha2beta2gamma3 heterotrimeric complex of human AMP-activated protein kinase.

AMP-activated protein kinase (AMPK) is an energy-sensing serine/threonine protein kinase that plays a central role in whole-body energy homeostasis. AMPK is a heterotrimeric enzyme with a catalytic (alpha) subunit and two regulatory (beta and gamma) subunits. The muscle-specific AMPK heterotrimeric complex (alpha2beta2gamma3) is involved in glucose and fat metabolism in skeletal muscle and therefore has emerged as an attractive target for drug development for diabetes and metabolic syndrome.

Binding to the low-density lipoprotein receptor accelerates futile catalytic cycling in PCSK9 and raises the equilibrium level of intramolecular acylenzyme.

Proprotein convertase subtilisin-kexin type 9 (PCSK9) binds to the low-density lipoprotein receptor (LDLR) on target cells and lowers the level of receptor by impeding its recycling. PCSK9 is self-processed to a complex of its prodomain and catalytic domain like a typical protein convertase, but it does not develop normal proteolytic activity. Instead, its propeptide remains complexed with the catalytic domain, and the C-terminal Gln152 of the prodomain occupies the active site like a substrate for peptide synthesis.

Biophysical and biochemical approach to locating an inhibitor binding site on cholesteryl ester transfer protein.

Cholesteryl ester transfer protein (CETP) transfers neutral lipids between different types of plasma lipoprotein. Inhibitors of CETP elevate the fraction of plasma cholesterol associated with high-density lipoproteins and are being developed as new agents for the prevention and treatment of cardiovascular disease. The molecular basis of their function is not yet fully understood.

The 2.0 A crystal structure of the ERalpha ligand-binding domain complexed with lasofoxifene.

Lasofoxifene is a new and potent selective estrogen receptor modulator (SERM). The structural basis of its interaction with the estrogen receptor has been investigated by crystallographic analysis of its complex with the ligand-binding domain of estrogen receptor alpha at a resolution of 2.0 A.

Structural and biophysical studies of PCSK9 and its mutants linked to familial hypercholesterolemia.

Proprotein convertase subtilisin kexin type 9 (PCSK9) lowers the abundance of surface low-density lipoprotein (LDL) receptor through an undefined mechanism. The structure of human PCSK9 shows the subtilisin-like catalytic site blocked by the prodomain in a noncovalent complex and inaccessible to exogenous ligands, and that the C-terminal domain has a novel fold. Biosensor studies show that PCSK9 binds the extracellular domain of LDL receptor with K(d) = 170 nM at the neutral pH of plasma, but with a K(d) as low as 1 nM at the acidic pH of endosomes.

Crystal structure of cholesteryl ester transfer protein reveals a long tunnel and four bound lipid molecules.

Cholesteryl ester transfer protein (CETP) shuttles various lipids between lipoproteins, resulting in the net transfer of cholesteryl esters from atheroprotective, high-density lipoproteins (HDL) to atherogenic, lower-density species. Inhibition of CETP raises HDL cholesterol and may potentially be used to treat cardiovascular disease. Here we describe the structure of CETP at 2.

Expression and protein chemistry yielding crystallization of the catalytic domain of ADAM17 complexed with a hydroxamate inhibitor.

The membrane-anchored metalloproteinase ADAM17 (TNF-alpha converting enzyme; TACE; EC 3.4.24.

Cyclization of N-terminal S-carbamoylmethylcysteine causing loss of 17 Da from peptides and extra peaks in peptide maps.

Enzymatic digests of proteins S-alkylated with iodoacetamide may contain peptides with N-terminal S-carbamoylmethylcysteine. These can be partly converted to a form with 17 Da lower mass and increased HPLC retention. Proof by synthesis supported by MS/MS and NMR spectroscopy was used to show that N-terminal S-carbamoylmethyl-L-cysteine can cyclize, losing NH3 to form an N-terminal residue of (R)-5-oxoperhydro-1,4-thiazine-3-carboxylic acid.

Glutathione s-transferase omega 1-1 is a target of cytokine release inhibitory drugs and may be responsible for their effect on interleukin-1beta posttranslational processing.

Stimulus-induced posttranslational processing of human monocyte interleukin-1beta (IL-1beta) is accompanied by major changes to the intracellular ionic environment, activation of caspase-1, and cell death. Certain diarylsulfonylureas inhibit this response, and are designated cytokine release inhibitory drugs (CRIDs). CRIDs arrest activated monocytes so that caspase-1 remains inactive and plasma membrane latency is preserved.

Kinetic analysis of estrogen receptor/ligand interactions.

Surface plasmon resonance biosensor technology was used to directly measure the binding interactions of small molecules to the ligand-binding domain of human estrogen receptor. In a screening mode, specific ligands of the receptor were easily discerned from nonligands. In a high-resolution mode, the association and dissociation phase binding responses were shown to be reproducible and could be fit globally to a simple interaction model to extract reaction rate constants.

Synthesis and biological activity of selective pipecolic acid-based TNF-alpha converting enzyme (TACE) inhibitors.

A series of novel, selective TNF-alpha converting enzyme inhibitors based on 4-hydroxy and 5-hydroxy pipecolate hydroxamic acid scaffolds is described. The potency and selectivity of TACE inhibition is dramatically influenced by the nature of the sulfonamide group which interacts with the S1' site of the enzyme. Substituted 4-benzyloxybenzenesulfonamides exhibit excellent TACE potency with >100x selectivity over inhibition of matrix metalloprotease-1 (MMP-1).