Research Topics
Species | Z GuanSummaryAffiliation: Merck Research Laboratories Country: USA Publications
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Detail Information
Publications
Solvation of acylium fragment ions in electrospray ionization quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometryZ Guan
Merck Research Laboratories, P O Box 2000, Rahway, New Jersey 07065, USA
J Mass Spectrom 36:264-76. 2001..High-resolution accurate mass measurements are important in establishing the elemental compositions of these adduct species and preventing erroneous data interpretation...- Detection and characterization of methionine oxidation in peptides by collision-induced dissociation and electron capture dissociationZiqiang Guan
Merck Research Laboratories, Rahway, New Jersey 07065, USA
J Am Soc Mass Spectrom 14:605-13. 2003.... - Identification and localization of the fatty acid modification in ghrelin by electron capture dissociationZiqiang Guan
Molecular Profiling Proteomics, Merck Research Laboratories, Rahway, New Jersey 07065, USA
J Am Soc Mass Spectrom 13:1443-7. 2002..The chemical composition of the attached fatty acid can be directly obtained from the accurate Fourier transform ion cyclotron resonance (FTICR) mass measurement of the ester bond cleavage product ions... - Isolation and insecticidal activity of mellamide from Aspergillus melleusJ G Ondeyka
Natural Products Chemistry, Merck Research Laboratories, R80Y 355, PO Box 2000, NJ 07065, Rahway, USA
J Ind Microbiol Biotechnol 30:220-4. 2003..HR-FTMS aided in the molecular weight and formula determination. Mellamide showed in vitro insecticidal activity in bioassays against larvae of Lucilia sericata and Aedes egypti with LD(90) of 1,000 and 50 micro g/ml, respectively... 
Structure and biosynthesis of free lipid A molecules that replace lipopolysaccharide in Francisella tularensis subsp. novicidaXiaoyuan Wang
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
Biochemistry 45:14427-40. 2006..Formation of free lipid A in F. tularensis subsp. novicida might be initiated by an unusual Kdo hydrolase present in the membranes of this organism...- Anthrabenzoxocinones from Streptomyces sp. as liver X receptor ligands and antibacterial agentsKithsiri B Herath
Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 68:1437-40. 2005..5-2 microg/mL). Details of the isolation, structure elucidation, LXR ligand binding, antibacterial activity, and selectivity of inhibition of 1 and 2 are described... - New fungal metabolite geranylgeranyltransferase inhibitors with antifungal activitySheo B Singh
Merck Research Laboratories, P O Box 2000, Rahway, NJ 07065, USA
Nat Prod Res 19:739-47. 2005..Isolation, structure elucidation, GGTase I inhibitory activities and antifungal activities of these compounds are described... - Steroidal and triterpenoidal fungal metabolites as ligands of liver X receptorsJohn G Ondeyka
Merck Research Laboratories, P. O. Box 2000, Rahway, New Jersey 07065, USA
J Antibiot (Tokyo) 58:559-65. 2005..The isolation and LXR activity of these compounds are described... - A slow, tight-binding inhibitor of the zinc-dependent deacetylase LpxC of lipid A biosynthesis with antibiotic activity comparable to ciprofloxacinAmanda L McClerren
Department of Biochemistry, Duke University Medical Center, Post Office Box 3711, Durham, North Carolina 27710, USA
Biochemistry 44:16574-83. 2005..CHIR-090 is the first example of a slow, tight-binding inhibitor for LpxC and may be the prototype for a new generation of LpxC inhibitors with therapeutic applicability... - Isolation and structures of novel fungal metabolites as chemokine receptor (CCR2) antagonistsKithsiri B Herath
Merck Research Laboratories, Rahway, NJ 07065, USA
J Antibiot (Tokyo) 58:686-94. 2005..Cytochalasins A and B represented the second group and inhibited the binding activity with IC50 values of 5 and 188 microM, respectively. This is the first report of natural product antagonists of the CCR2 receptor... - Highly substituted terphenyls as inhibitors of parasite cGMP-dependent protein kinase activityChaowei Zhang
Natural Products Chemistry and Human and Animal Infectious Disease, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA
J Nat Prod 69:710-2. 2006..by a high-throughput two-step isolation method employing LH-20 and reversed-phase HPLC. These compounds inhibited parasite PKG with IC(50) values in the range 0.9-5.8 microM... - Identification of N-acylphosphatidylserine molecules in eukaryotic cellsZiqiang Guan
Department of Biochemistry, Duke University Medical Center, P O Box 3711, Durham, North Carolina 27710, USA
Biochemistry 46:14500-13. 2007..We suggest that a phospholipase D might cleave N-acyl-PS to generate N-acylserine, in analogy to the biosynthesis of the endocannabinoid N-arachidonoylethanolamine (anadamide) from N-arachidonoylphosphatidylethanolamine... - Isolation and insecticidal/anthelmintic activity of xanthonol, a novel bis-xanthone, from a non-sporulating fungal speciesJohn G Ondeyka
Merck Research Laboratories, Merck and Co, Inc PO BOX 2000, R80Y 355, Rahway, New Jersey 07065, USA
J Antibiot (Tokyo) 59:288-92. 2006..Xanthonol exhibited insecticidal and anthelmintic activities against larvae of Lucilia sericata, Aedes aegypti, and Haemonchus contortus with LD90 of 33, 8, and 50 microg/ml, respectively... - Isolation, structure, and coccidiostat activity of coccidiostatin AHiranthi Jayasuriya
Merck Research Laboratories, P O Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 70:1364-7. 2007..The isolation, structure elucidation, relative configuration, and activity of coccidiostatin A (2) are described... - Diterpenoid, steroid, and triterpenoid agonists of liver X receptors from diversified terrestrial plants and marine sourcesHiranthi Jayasuriya
Merck Research Laboratories, P O Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 68:1247-52. 2005..In general these compounds were selective for the LXR alpha-receptor over the beta-receptor in all assays and were much better stimulators of the alpha-receptor than the endogenous steroid ligands... - Guttiferone I, a new prenylated benzophenone from Garcinia humilis as a liver X receptor ligandKithsiri Herath
Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 68:617-9. 2005..The IC(50) value for this compound in the LXRalpha-SPA binding assay was 3.4 muM. Details of the isolation, structure elucidation, and ligand binding activity of 1 are described... - Isolation, structure, and HIV-1 integrase inhibitory activity of Cytosporic acid, a fungal metabolite produced by a Cytospora spHiranthi Jayasuriya
Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 66:551-3. 2003..collected from Puerto Rico. It inhibited strand transfer reaction of HIV-1 integrase with an IC(50) of 20 microM. The isolation, structure elucidation, relative stereochemistry, and activity of 1 are described... - The unanticipated loss of SO2 from sulfonamides in collision-induced dissociationZhen Wang
Department of Drug Metabolism, Merck Research Laboratories, Rahway, NJ 07065 0900, USA
Rapid Commun Mass Spectrom 17:81-6. 2003..The neutral loss involving the cleavage of two bonds was unanticipated and suggested a complex rearrangement process. A mechanism for the loss of SO(2) has been proposed... - Isolation, structure, and HIV-1-integrase inhibitory activity of structurally diverse fungal metabolitesSheo B Singh
Natural Products Chemistry, Merck Research Laboratories, P O Box 2000, Rahway, New Jersey 07065, USA
J Ind Microbiol Biotechnol 30:721-31. 2003..5-120 micro M. The bioassay-directed isolation, structure elucidation, and HIV-1 inhibitory activity of these compounds are described... - Durhamycin A, a potent inhibitor of HIV Tat transactivationHiranthi Jayasuriya
Merck Research Laboratories, P O Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 65:1091-5. 2002..Three other novel analogues, durhamycin B (2), compound (3), and the aglycone (4), were also discovered or chemically prepared that were less potent than durhamycin A... - Isolation, structure, absolute stereochemistry, and HIV-1 integrase inhibitory activity of integrasone, a novel fungal polyketideKithsiri B Herath
Natural Products Chemistry, Merck Research Laboratories, PO Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 67:872-4. 2004..This bicyclic dihydroxy epoxide lactone inhibited the strand transfer reaction of HIV-1 integrase with an IC(50) of 41 microM... - Isolation and structure of antagonists of chemokine receptor (CCR5)Hiranthi Jayasuriya
Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 67:1036-8. 2004..Anibamine.TFA competed for the binding of 125I-gp120 to human CCR5 with an IC50 of 1 microM. Ophiobolin C and 19,20-epoxycytochalasin Q exhibited binding IC50) values of 40 and 60 microM, respectively... - Integramides A and B, two novel non-ribosomal linear peptides containing nine C(alpha)-methyl amino acids produced by fungal fermentations that are inhibitors of HIV-1 integraseSheo B Singh
Merck Research Laboratories, Rahway, New Jersey 07065, and West Point, Pennsylvania 19486, USA
Org Lett 4:1431-4. 2002..Integramides A and B inhibited the coupled reaction of HIV-1 integrase with IC50 values of 17 and 10 microM, respectively... - Discovery of structurally diverse natural product antagonists of chemokine receptor CXCR3John G Ondeykal
Merck Research Laboratories, Rahway, NJ, USA
Mol Divers 9:123-9. 2005..Diosgenin glycosides dioscin, hypoglaucin A and kallstroemin D exhibited IC50 values of 2.1, 0.47 and 3 microM, respectively. A novel cyclic 3-alkyl pyridinium salt isolated from a sponge displayed a binding IC50 of 0.67 microM... - Tenellones A and B from a Diaporthe sp.: two highly substituted benzophenone inhibitors of parasite cGMP-dependent protein kinase activityChaowei Zhang
Natural Products Chemistry and Human and Animal Infectious Disease, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA
J Nat Prod 68:611-3. 2005..Bioassay-guided fractionation of the microbial extracts has led to the discovery of tenellones A (2) and B (3), two new highly substituted benzophenones. The isolation, structure, and activity of these compounds are described... - Analysis of ubiquinones, dolichols, and dolichol diphosphate-oligosaccharides by liquid chromatography-electrospray ionization-mass spectrometryTeresa A Garrett
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
Methods Enzymol 432:117-43. 2007..We also present a new MS-based method for the detection and structural characterization of the intact dolichol diphosphate oligosaccharide Dol-PP-(GlcNAc)2 (Man)9(Glc)3 from porcine pancreas... - An undecaprenyl phosphate-aminoarabinose flippase required for polymyxin resistance in Escherichia coliAixin Yan
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
J Biol Chem 282:36077-89. 2007..PmrM and PmrL, now renamed ArnE and ArnF because of their involvement in L-Ara4N modification of lipid A, may be subunits of an undecaprenyl phosphate-alpha-L-Ara4N flippase... - An inner membrane dioxygenase that generates the 2-hydroxymyristate moiety of Salmonella lipid AHenry S Gibbons
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
Biochemistry 47:2814-25. 2008..LpxO is an unusual example of an integral membrane protein that is a member of the Fe (2+)/O 2/alpha-ketoglutarate-dependent dioxygenase family... - The active conformation of beta-arrestin1: direct evidence for the phosphate sensor in the N-domain and conformational differences in the active states of beta-arrestins1 and -2Kelly N Nobles
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
J Biol Chem 282:21370-81. 2007..This study represents the first direct evidence that the "receptor-bound" conformations of beta-arrestins1 and 2 are different... - Identification and quantification of dolichol and dolichoic acid in neuromelanin from substantia nigra of the human brainWeslyn C Ward
Department of Chemistry, Duke University, Durham, NC, USA
J Lipid Res 48:1457-62. 2007..The distribution of dol-CA chains lengths in NM also differed from that of dol, suggesting that the enzyme(s) responsible for the conversion of dol to dol-CA prefer a dolichol substrate containing 19 isoprene units... - Attenuated virulence of a Francisella mutant lacking the lipid A 4'-phosphataseXiaoyuan Wang
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
Proc Natl Acad Sci U S A 104:4136-41. 2007..Francisella lpxF mutants may be useful for immunization against tularemia... - Modification of cysteine 111 in human Cu,Zn-superoxide dismutaseAyako Okado-Matsumoto
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
Free Radic Biol Med 41:1837-46. 2006.... - Electron capture dissociation mass spectrometry in characterization of post-translational modificationsRay Bakhtiar
Merck Research Laboratories, Rahway, NJ 07065, USA
Biochem Biophys Res Commun 334:1-8. 2005..Herein, we present a general overview of the ECD technique as well as selected applications in characterization of post-translationally modified polypeptides... - Electron capture dissociation mass spectrometry in characterization of peptides and proteinsRay Bakhtiar
Merck Research Laboratories, Rahway, NJ 07065, USA
Biotechnol Lett 28:1047-59. 2006..A recent technique, coined as electron transfer dissociation (ETD), will be also discussed briefly... - Identification of candidate substrates for ectodomain shedding by the metalloprotease-disintegrin ADAM8Silvia Naus
Entwicklungsbiologie und Molekulare Pathologie, W7, , D-33615 Bielefeld, Germany
Biol Chem 387:337-46. 2006..Taken together, the results allowed us to identify novel candidate substrates that could be cleaved by ADAM8 in vivo under pathologic conditions... - Expression cloning of three Rhizobium leguminosarum lipopolysaccharide core galacturonosyltransferasesSuparna Kanjilal-Kolar
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
J Biol Chem 281:12865-78. 2006..No in vitro activity was detected when RgtA was expressed in Escherichia coli unless Rhizobiaceae membranes were also included... - Kinetic analysis of the zinc-dependent deacetylase in the lipid A biosynthetic pathwayAmanda L McClerren
Department of Biochemistry, Duke University Medical Center, P O Box 3813, Durham, North Carolina 27710, USA
Biochemistry 44:1106-13. 2005..007%, and 0.57%, respectively) suggest that they contribute significantly to catalysis. Our cumulative data support a mechanism for LpxC wherein Glu73 serves as the general base for deprotonation and activation of the zinc-bound water... - Modulation of human nuclear receptor LRH-1 activity by phospholipids and SHPEric A Ortlund
Department of Chemistry, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, 27599, USA
Nat Struct Mol Biol 12:357-63. 2005..Our results indicate that hLRH-1's control of gene expression is mediated by phospholipid binding, and establish hLRH-1 as a novel target for compounds designed to slow breast cancer development... - Solution structure of the Set2-Rpb1 interacting domain of human Set2 and its interaction with the hyperphosphorylated C-terminal domain of Rpb1Ming Li
Department of Biochemistry, Duke University Medical Center, Research Drive, Durham, NC 27710, USA
Proc Natl Acad Sci U S A 102:17636-41. 2005..In view of the differential effects of these point mutations on binding to different CTD phosphopeptides, we propose a model for the hSRI domain interaction with the PCTD... - Purification and mutagenesis of LpxL, the lauroyltransferase of Escherichia coli lipid A biosynthesisDavid A Six
Department of Biochemistry, Duke University Medical Center, P O Box 3711, Durham, North Carolina 27710, USA
Biochemistry 47:8623-37. 2008..Our results show that the acyltransferases that generate the secondary acyl chains of lipid A are members of the GPAT family and set the stage for structural studies...