Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
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Human macrophage elastase (MMP-12) plays an important role in inflammatory processes and has been implicated in diseases such as emphysema and chronic obstructive pulmonary disease (COPD). It is therefore an attractive target for therapeutic agents. As part of a structure-based drug design programme to find new inhibitors of MMP-12, the crystal structures of the MMP-12 catalytic domain (residues 106-268) complexed to three different non-peptidic small molecule inhibitors have been determined. The structures reveal that all three ligands bind in the S1' pocket but show varying degrees of interaction with the Zn atom. The structures of the complexes with inhibitors CP-271485 and PF-00356231 reveal that their central morpholinone and thiophene rings, respectively, sit over the Zn atom at a distance of approximately 5A, locating the inhibitors halfway down the S1' pocket. In both of these structures, an acetohydroxamate anion, an artefact of the crystallisation solution, chelates the zinc atom. By contrast, the acetohydroxamate anion is displaced by the ligand in the structure of MMP-12 complexed to PD-0359601 (Bayer), a potent zinc chelating N-substituted biaryl butyric acid, used as a reference compound for crystallisation. Although a racemate was used for the crystallisation, the S enantiomer only is bound in the crystal. Important hydrophobic interactions between the inhibitors and residues from the S1' pocket are observed in all of the structures. The relative selectivity displayed by these ligands for MMP-12 over other MMP family members is discussed.
J Mol Biol 2004 Aug 20
PMID:Crystal structures of novel non-peptidic, non-zinc chelating inhibitors bound to MMP-12. 1528 3

Molecular modeling has been used to assist in the development of a novel series of potent glycogen phosphorylase inhibitors based on a phenyl diacid lead, compound 1. In the absence of suitable competitive binding assays, compound 1 was predicted to bind at the AMP allosteric site based on superposition onto known inhibitors which bind at different sites in the enzyme and analyses of the surrounding protein environment associated with these distinct sites. Possible docking modes of compound 1 at the AMP allosteric site were further explored using the crystal structure of rabbit muscle glycogen phosphorylase complexed with a Bayer diacid compound W1807 (PDB entry 3AMV). Compound 1 was predicted to interact with positively charged arginines at the AMP allosteric site in the docking model. Characterization of the binding pocket by a grid-based surface calculation of the docking model revealed a large unfilled hydrophobic region near the central phenyl ring, suggesting that compounds with larger hydrophobic groups in this region would improve binding. A series of naphthyl diacid compounds were designed and synthesized to access this hydrophobic cleft, and showed significantly improved potency.
J Mol Graph Model 2005 Apr
PMID:Modeling aided design of potent glycogen phosphorylase inhibitors. 1578 Nov 88

Cyclic nucleotide phosphodiesterases (PDEs) have been investigated for years as targets for therapeutic intervention in a number of pathophysiological processes. Phosphodiesterase-5 (PDE5), which is highly specific for guanosine 3'-5'-cyclic-monophosphate (cGMP) at both its catalytic site and its allosteric sites, has generated particular interest because it is potently and specifically inhibited by three drugs: sildenafil (Viagra, Pfizer), tadalafil (Cialis, Lilly-ICOS), and vardenafil (Levitra, Bayer GSK). Previously, we have used [(3)H]cGMP to directly study the interaction of cGMP with the allosteric sites of PDE5, but because cGMP binds with relatively low affinity to the catalytic site, it has been difficult to devise a binding assay for this particular binding reaction. This approach using measurement of radiolabeled ligand binding continues to allow us to more precisely define functional features of the enzyme. We now use a similar approach to study the characteristics of high-affinity [(3)H]inhibitor binding to the PDE5 catalytic domain. For these studies, we have prepared [(3)H]sildenafil and [(3)H]tadalafil, two structurally different competitive inhibitors of PDE5. The results demonstrate that radiolabeled ligands can be used as probes for both catalytic site and allosteric site functions of PDE5. We describe herein the methods that we have established for studying the binding of radiolabeled ligands to both types of sites on PDE5. These techniques have also been successfully applied to the study of binding of radiolabeled PDE5 inhibitors to PDE11, suggesting that these methods are applicable to the study of other PDEs, and perhaps other enzyme families.
Methods Mol Biol 2005
PMID:Radiolabeled ligand binding to the catalytic or allosteric sites of PDE5 and PDE11. 1598 68

We report the experimental preparation of the 1,3-butanal-1,2,4,5-tetroxane by oxidation of glutataldehyde with oxygen peroxide in presence of concentrated sulfuric acid, following the Bayer and Viller method modified by Jorge et al. The UV and IR spectra are studied from the experimental and theoretical standpoint. A rather complete vibrational assignment was performed and the nature of the electronic transitions was discussed in detail.
Spectrochim Acta A Mol Biomol Spectrosc 2006 Jun
PMID:Experimental preparation and UV/IR spectroscopic characterization of 1,3-dibutanal-1,2,4,5-tetroxane. 1644 38

We investigate the use of different Machine Learning methods to construct models for aqueous solubility. Models are based on about 4000 compounds, including an in-house set of 632 drug discovery molecules of Bayer Schering Pharma. For each method, we also consider an appropriate method to obtain error bars, in order to estimate the domain of applicability (DOA) for each model. Here, we investigate error bars from a Bayesian model (Gaussian Process (GP)), an ensemble based approach (Random Forest), and approaches based on the Mahalanobis distance to training data (for Support Vector Machine and Ridge Regression models). We evaluate all approaches in terms of their prediction accuracy (in cross-validation, and on an external validation set of 536 molecules) and in how far the individual error bars can faithfully represent the actual prediction error.
J Comput Aided Mol Des 2007 Sep
PMID:Estimating the domain of applicability for machine learning QSAR models: a study on aqueous solubility of drug discovery molecules. 1763 88

Unfavorable lipophilicity and water solubility cause many drug failures; therefore these properties have to be taken into account early on in lead discovery. Commercial tools for predicting lipophilicity usually have been trained on small and neutral molecules, and are thus often unable to accurately predict in-house data. Using a modern Bayesian machine learning algorithm--a Gaussian process model--this study constructs a log D7 model based on 14,556 drug discovery compounds of Bayer Schering Pharma. Performance is compared with support vector machines, decision trees, ridge regression, and four commercial tools. In a blind test on 7013 new measurements from the last months (including compounds from new projects) 81% were predicted correctly within 1 log unit, compared to only 44% achieved by commercial software. Additional evaluations using public data are presented. We consider error bars for each method (model based error bars, ensemble based, and distance based approaches), and investigate how well they quantify the domain of applicability of each model.
Mol Pharm
PMID:Machine learning models for lipophilicity and their domain of applicability. 1763 64

We investigate the use of different Machine Learning methods to construct models for aqueous solubility. Models are based on about 4000 compounds, including an in-house set of 632 drug discovery molecules of Bayer Schering Pharma. For each method, we also consider an appropriate method to obtain error bars, in order to estimate the domain of applicability (DOA) for each model. Here, we investigate error bars from a Bayesian model (Gaussian Process (GP)), an ensemble based approach (Random Forest), and approaches based on the Mahalanobis distance to training data (for Support Vector Machine and Ridge Regression models). We evaluate all approaches in terms of their prediction accuracy (in cross-validation, and on an external validation set of 536 molecules) and in how far the individual error bars can faithfully represent the actual prediction error.
J Comput Aided Mol Des 2007 Dec
PMID:Estimating the domain of applicability for machine learning QSAR models: a study on aqueous solubility of drug discovery molecules. 1806 May 5

Automated electrophysiological assays are of great importance for modern drug discovery, and various approaches have been developed into practical devices. Here, we describe the automation of two-electrode voltage-clamp (TEVC) recording from Xenopus oocytes using the Roboocyte automated workstation, jointly developed by Multi Channel Systems and Bayer Technology Services. We briefly discuss the technology, including its advantages and limitations relative to patch clamp and other TEVC systems. We provide a step-by-step description of typical operating procedures and show that the Roboocyte represents a practical and highly effective way to perform automated electrophysiology in an industrial setting.
Methods Mol Biol 2007
PMID:The roboocyte: automated electrophysiology based on Xenopus oocytes. 1882 89

Cancer, being a major healthcare concern worldwide, is one of the main targets for the application of emerging proteomic technologies and these tools promise to revolutionize the way cancer will be diagnosed and treated in the near future. Today, as a result of the unprecedented advances that have taken place in molecular biology, cell biology and genomics there is a pressing need to accelerate the translation of basic discoveries into clinical applications. This need, compounded by mounting evidence that cellular model systems are unable to fully recapitulate all biological aspects of human dissease, is driving scientists to increasingly use clinically relevant samples for biomarker and target discovery. Tissues are heterogeneous and as a result optimization of sample preparation is critical for generating accurate, representative, and highly reproducible quantitative data. Although a large number of protocols for preparation of tissue lysates has been published, so far no single recipe is able to provide a "one-size fits all" solubilization procedure that can be used to analyse the same lysate using different proteomics technologies. Here we present evidence showing that cell lysis buffer 1 (CLB1), a lysis solution commercialized by Zeptosens [a division of Bayer (Schweiz) AG], provides excellent sample solubilization and very high 2D PAGE protein resolution both when using carrier ampholytes and immobilized pH gradient strips. Moreover, this buffer can also be used for array-based proteomics (reverse-phase lysate arrays or direct antibody arrays), allowing the direct comparison of qualitative and quantitative data yielded by these technologies when applied to the same samples. The usefulness of the CLB1 solution for gel-based proteomics was further established by 2D PAGE analysis of a number of technically demanding specimens such as breast carcinoma core needle biopsies and problematic tissues such as brain cortex, cerebellum, skeletal muscle, kidney cortex and tongue. This solution when combined with a specific sample preparation technique - cryostat sectioning of frozen specimens - simplifies tissue sample preparation and solves most of the difficulties associated with the integration of data generated by different proteomic technologies.
Mol Oncol 2008 Dec
PMID:A single lysis solution for the analysis of tissue samples by different proteomic technologies. 1938 58

Genotoxicity assays were conducted on rats treated with benzo[a]pyrene (BaP) as part of Stage III of a validation study on the Pig-a gene mutation assay. Assays were performed at the U.S. FDA-NCTR and Bayer-Germany. Starting on Day 1, groups of five 6- to 7-week-old male Fischer 344 (F344, used at FDA-NCTR) and Han Wistar rats (Bayer) were given 28 daily doses of 0, 37.5, 75, or 150 mg/kg BaP; blood was sampled on Days -1, 4, 15, 29, and 56. Pig-a mutant frequencies were determined on Days -1, 15, 29, and 56 in total red blood cells (RBCs) and reticulocytes (RETs) as RBC(CD59-) and RET(CD59-) frequencies; percent micronucleated-RETs (%MN-RET) were measured on Days 4 and 29. RBC(CD59-) and RET(CD59-) frequencies increased in a dose- and time-dependent manner, producing significant increases by Day 29 in both rat models. The responses for RETs were stronger than those for RBCs, and the responses in F344 rats were stronger than in Han Wistar rats. BaP also produced significant increases in %MN-RET frequency at Days 4 and 29, with the responses being greater in F344 than Han Wistar rats. The overall findings were consistent with those of the reference laboratory using Han Wistar rats. Finally, mutation assays performed on splenocytes from Day 56 F344 rats indicated that BaP mutant frequencies were three to fivefold higher for the Hprt gene than the Pig-a gene. The results indicate that the Pig-a RET and RBC assays are reproducible, transferable, and show promise for integrating gene mutation into 28-day repeat-dose studies.
Environ Mol Mutagen 2011 Dec
PMID:Report on stage III Pig-a mutation assays using benzo[a]pyrene. 2205 32


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