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KRASG12Chas emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-“undruggable” target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12Cto identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12Cinhibitor currently in phase I clinical trials (NCT03600883).

Pim kinases are a family of constitutively active serine/threonine kinases that are partially redundant and regulate multiple pathways important for cell growth and survival. In human disease, high expression of the three Pim isoforms has been implicated in the progression of hematopoietic and solid tumor cancers, which suggests that Pim kinase inhibitors could provide patients with therapeutic benefit. Herein, we describe the structure-guided optimization of a series of quinazolinone-pyrrolodihydropyrrolone analogs leading to the identification of potent pan-Pim inhibitor 28with improved potency, solubility, and drug-like properties. Compound 28demonstrated on-target Pim activity in an in vivo pharmacodynamic assay with significant inhibition of BAD phosphorylation in KMS-12-BM multiple myeloma tumors for 16 h postdose. In a 2-week mouse xenograft model, daily dosing of compound 28resulted in 33% tumor regression at 100 mg/kg.

An experimental study of mixing of various particulates into synthetic elastomers and polypropylene is presented. For the elastomers, a batch internal mixer and a commercial continuous mixer were used to disperse various small particles including silica, carbon black, and CaCO3. For the polypropylene, this same continuous mixer plus a Buss Kneader, co-rotating twin screw extruder and an intermeshing counter-rotating twin screw extruder with different modular screw configurations were used to follow the dispersion of CaCO3. The breakage of glass fibers in these machines was also followed. Generally the most severe breakage of agglomerates and glass fiber was by modular intermeshing counter-rotating screws with special Leistritz elements. A model was developed for breakdown of agglomerates and fibers. The agreement with experiment was promising.

The authors give two cohomology vanishing theorems for domains, which are not pseudoconvex, and characterize the holomorphy of domains with smooth boundaries in separable Hilbert spaces through cohomology vanishing.

For μ≥0 , we consider a linear operator Lμ:A→A defined by the convolution fμ∗f , where fμ=(1−μ)z2F1(a,b,c;z)+μz(z2F1(a,b,c;z))′ . Let ϕ∗(A,B) denote the class of normalized functions f which are analytic in the open unit disk and satisfy the condition zf′/f≺(1+Az)/1+Bz , −1≤A0 , (β<1) . The main object of this paper is to establish the connection between Rη(β) and ϕ∗(A,B) involving the operator Lμ(f) . Furthermore, we treat the convolution I=∫0z(fμ(t)/t)dt ∗f(z) for f∈Rη(β) .

This paper shows that the $\bar \partial$-problem for holomorphic (0, 2)-forms on Hilbert spaces is solvable on pseudoconvex open subsets. By using this result, the authors investigate the existence of the solution of the $\bar \partial$-equation for holomorphic (0, 2)-forms on pseudoconvex domains in D.F.N. spaces.

Residence time distributions were measured for a Buss Kneader, Kobelco Nex-T continuous mixer as well as intermeshing co-rotating and counter-rotating twin screw extruders using polypropylene with aluminum flakes as a marker. Various modular screw configurations, screw speeds and feed rates were considered. Increasing feed rate and increasing screw speed the mean residence to shorter values and narrows the residence time distribution. Generally, in comparison of the different machines, the intermeshing counter-rotating twin screw extruder has the shortest mean residence time and narrowest distribution of residence times, while the Buss Kneader has the longest mean residence time and broadest residence time distribution.

The membrane bound form of bacteriophage fd coat protein has a long hydrophobic membrane spanning helix and a shorter amphipathic helix in the plane of the bilayer. Residues near the N and C termini and in the turn connecting the two helices are mobile. The locations and orientations of the helical secondary structure elements and the protein backbone dynamics were characterized by combining results from multidimensional solution NMR experiments on protein samples in micelles and high resolution solid-state NMR experiments on protein samples in oriented and unoriented lipid bilayers. The coat protein is a monomer in micelles. The secondary structure of the membrane bound form of fd coat protein is very similar to that of the structural form found in the virus particles, since it is nearly all alpha helix. However, the membrane bound form of the protein differs from the structural form of the protein in virus particles in the arrangement of the secondary structure, since the membrane bound form of the protein has two distinct helical domains oriented perpendicular to each other and the structural form of the protein in the virus particles has a nearly continuous helix aligned approximately along the filament axis. In addition, there are substantial differences in the dynamics of residues in the bend between the two helices and near the C terminus, since they are mobile in the membrane bound form of the protein and not in the virus particles. Residues 1 to 5 at the N terminus are highly mobile and unstructured in both the membrane bound and structural forms of the coat protein. Copyright 1993, 1999 Academic Press

We describe the isolation and characterization of two peptide toxins from Conus ermineus venom targeted to nicotinic acetylcholine receptors (nAChRs). The peptide structures have been confirmed by mass spectrometry and chemical synthesis. In contrast to the 12-18 residue, 4 Cys-containing alpha-conotoxins, the new toxins have 30 residues and 6 Cys residues. The toxins, named alphaA-conotoxins EIVA and EIVB, block both Torpedo and mouse alpha1-containing muscle subtype nAChRs expressed in Xenopus oocytes at low nanomolar concentrations. In contrast to alpha-bungarotoxin, alphaA-EIVA is inactive at alpha7-containing nAChRs even at micromolar concentrations. In this regard, alphaA-EIVA is similar to the previously described alpha-conotoxins (e.g. alpha-MI and alpha-GI) which also selectively target alpha1- versus alpha7-containing nAChRs. However, alpha-MI and alpha-GI discriminate between the alpha/delta versus alpha/gamma subunit interfaces of the mouse muscle nAChR with 10,000-fold selectivity. In contrast, alphaA-conotoxin EIVA blocks both the alpha/gamma site and alpha/delta site with equally high affinity but with distinct kinetics. The alphaA-conotoxins thus represent novel probes for the alpha/gamma as well as the alpha/delta binding sites of the nAChR.

In this work, a new family of Conus peptides, the alpha A-conotoxins, which target the nicotinic acetylcholine receptor, is defined. The first members of this family have been characterized from the eastern Pacific species, Conus purpurascens (the purple cone); three peptides that cause paralysis in fish were purified and characterized from milked venom. The sequence and disulfide bonding pattern of one of these, alpha A-conotoxin PIVA, is as follows: [formula: see text] where O represents trans-4-hydroxyproline. The two other peptides purified from C. purpurascens venom are the under-hydroxylated derivatives, [Pro13]alpha A-conotoxin PIVA and [Pro7,13]alpha A-conotoxin PIVA. The peptides have been chemically synthesized in a biologically active form. Both electrophysiological experiments and competition binding with alpha-bungarotoxin demonstrate that alpha A-PIVA acts as an antagonist of the nicotinic acetylcholine receptor at the postsynaptic membrane.

We describe two new methods for locating the dew/bubble curves of fluids. One is a numerical method and the other an analytical method based on the use of series expansions. The utility of these two methods is illustrated by application to a simple one-component fluid model and to several model polydisperse fluids. The numerical method is based on a new geometric representation of the equilibrium conditions-similar in spirit to the geometric representations often used for solving the equilibrium conditions of pure fluids. Our calculations show that the series-expansion technique can be quite effective at producing accurate representations of the phase boundaries.

kappa-Conotoxin PVIIA (kappa-PVIIA), a 27-amino acid toxin from Conus purpurascens venom that inhibits the Shaker potassium channel, was chemically synthesized in a biologically active form. The disulfide connectivity of the peptide was determined. kappa-Conotoxin PVIIA has the following structure. This is the first Conus peptide known to target K+ channels. [structure: see text] Although the Shaker K+ channel is sensitive to kappa-PVIIA, the rat brain Kv1.1 subtype is resistant. Chimeras between Shaker and the Kv1.1 K+ channels were constructed and expressed in Xenopus oocytes. Only channels containing the putative pore-forming region between the fifth and sixth transmembrane domains of Shaker retained toxin sensitivity, indicating that the toxin target site is in this region of the channel. Evidence is presented that kappa-PVIIA interacts with the external tetraethyl-ammonium binding site on the Shaker channel. Although both kappa-PVIIA and charybdotoxin inhibit the Shaker channel, they must interact differently. The F425G Shaker mutation increases charybdotoxin affinity by 3 orders of magnitude but abolishes kappa-PVIIA sensitivity. The precursor sequence of kappa-PVIIA was deduced from a cDNA clone, revealing a prepropeptide comprising 72 amino acids. The N-terminal region of the kappa-PVIIA prepropeptide exhibits striking homology to the omega-, muO-, and delta-conotoxins. Thus, at least four pharmacologically distinct superfamilies of Conus peptides belong to the same "O" superfamily, with the omega- and kappa-conotoxins forming one branch, and the delta- and muO-conotoxins forming a second major branch.

Phosphorylation of two newly identified epidermal growth factor (EGF) receptor substrates, eps8 and eps15, which do not possess Src homology (SH2) domains, was investigated using EGF receptor mutants of the autophosphorylation sites and deletion mutants of the carboxyl-terminal region. Two mutants, F5, in which all five tyrosine autophosphorylation sites substituted by phenylalanine, and Dc 123F, in which four tyrosines were removed by deletion and the fifth (Tyr-992) was mutated into phenylalanine, phosphorylated eps8 and eps15 as efficiently as the wild-type receptor. In contrast, SH2-containing substrates, phospholipase C gamma, the GTPase-activating protein of Ras, the p85 subunit of phosphatidylinositol 3 kinase, and the Src and collagen homology protein, are not phosphorylated by the F5 and Dc 123F mutants. A longer EGF receptor deletion mutant, Dc 214, lacking all five autophosphorylation sites, was unable to phosphorylate eps15 but phosphorylated eps8 13-fold more than the wild-type receptor. To determine the EGF receptor region important for phosphorylation of eps8 and eps15, progressive deletion mutants lacking the final 123, 165, 196, and 214 COOH-terminal residues were used. eps8 phosphorylation was progressively increased in Dc 165, Dc 196, and Dc 214 EGF receptor mutants, indicating that removal of the final 214 COOH-terminal residues increases the phosphorylation of this substrate by the EGF receptor. In contrast, eps15 was phosphorylated by Dc 123 and Dc 165 EGF receptor mutants but not by Dc 196 and Dc 214 mutants. This indicates that a region of 30 residues located between Dc 165 and Dc 196 is essential for eps15 phosphorylation. This is the first demonstration of structural requirements in the EGF receptor COOH terminus for efficient phosphorylation of non-SH2-containing substrates. In addition, enhanced eps8 phosphorylation correlates well with the increased transforming potential of EGF receptor deletion mutants Dc 196 and Dc 214, suggesting that this substrate may be involved in mitogenic signaling.

1. The novel peptide toxin delta-conotoxin-GmVIA, recently purified by us from the mollusk-hunting snail Conus gloriamaris, induces convulsive-like contractions when injected into land snails but has no detectable effects in mammals. 2. At concentrations of 0.5-0.75 microM, the toxin induces action potential broadening and increased excitability of cultured Aplysia neurons. 3. Whole cell patch-clamp experiments on cultured Aplysia neurons revealed that the toxin does not alter potassium or calcium currents, but induces action potential broadening by slowing the inactivation kinetics of the sodium current. Under control conditions, the inactivation kinetics of the sodium current follows a single exponential with tau = 0.47 +/- 0.14 (SE) ms. After toxin application the sodium current inactivation is composed of two phases: an early phase with tau = 0.86 +/- 0.12 ms and a late phase of slowly inactivating sodium current with tau = 488 +/- 120 ms. In addition, the toxin shifts the voltage-dependent steady-state inactivation curve to more positive values and the steady-state activation curve to more negative values. These alterations are not associated with changes in the rise time or the peak value of the sodium current. 4. The novel delta-conotoxin-GmVIA, and the previously described "King Kong peptide," purified from another mollusk-hunting cone (Conus textile), share a similar cystein framework also found in the calcium channel blocking peptide omega-conotoxin but represent a new class of conotoxins with unusual specificity for molluscan sodium channels.

1. A 31-amino-acid peptide from the venom of the snail-hunting species Conus marmoreus, microO-conotoxin MrVIA, inhibits mammalian voltage-gated sodium channels through a novel mechanism distinct from saxitoxin, tetrodotoxin, or mu-conotoxin. 2. MicroO-Conotoxin MrVIA blocks rat brain type II sodium channels expressed in Xenopus oocytes (IC50 approximately 200 nM, Hill coefficient approximately 1.6 +/- 0.2, mean +/- SE). Channel activation/inactivation kinetics and current-voltage relationships were unperturbed. 3. MicroO-Conotoxin MrVIA does not cause phasic or use-dependent inhibition of sodium currents measured in Xenopus oocytes expressing rat brain type II sodium channels, but shifts the steady-state availability of these sodium channels to more hyperpolarized potentials. 4. MicroO-Conotoxin MrVIA inhibited rapidly inactivating sodium channel conductance in rat hippocampal cells in culture. The inhibition was rapidly reversible. 5. MicroO-Conotoxin MrVIA does not displace specific [3H]saxitoxin binding to either rat brain or Electrophorus electric organ sites, indicating inhibitory effects mediated through a binding site distinct from site I.

The effects of blend composition, melt viscosity of poly(acrylonitrile-butadiene-styrene) (ABS), and compatibilizing effect of poly(methyl methacrylate) (PMMA) on mechanical properties of ABS/polycarbonate (PC) blends at ABS-rich compositions were studied. As the content of PC was increased, impact strength and Vicat softening temperature (VST) were increased. As the melt viscosity of ABS was increased near to that of PC, finer distribution of dispersed PC phase and consequent enhanced impact strength and VST were observed. The compatibilizing effect of PMMA can be ascer-tained from the enhanced properties of ¼-inch notch impact strength, VST, tensilestrength, and the morphology observed by a scanning electron microscope. The improved adhesion of the ABS/PC interface by PMMA changed the fracture mechanism and reduced the notch sensitivity of blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 533–542, 1998

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For μ≥0, we consider a linear operator Lμ:A→A defined by the convolution fμ∗f, where fμ=(1−μ)z2F1(a,b,c;z)+μz(z2F1(a,b,c;z))′. Let φ∗(A,B) denote the class of normalized functions f which are analytic in the open unit disk and satisfy the condition zf′/f≺(1+Az)/1+Bz, −1≤A0, (β<1). The main object of this paper is to establish the connection between Rη(β) and φ∗(A,B) involving the operator Lμ(f). Furthermore, we treat the convolution I=∫0z(fμ(t)/t)dt ∗f(z) for f∈Rη(β).