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Cooks RG, Zhang D, Koch KJ, Gozzo FC, Eberlin MN. Chiroselective self-directed octamerization of serine: implications for homochirogenesis. Anal Chem 2001; 73:3646-55. [PMID: 11510829 DOI: 10.1021/ac010284l] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Serine undergoes chiroselective self-directed oligomerization to form a singly protonated octamer under positive ion electrospray conditions, as identified by ion trap tandem mass spectrometry. The experiments also show a series of higher-order clusters (metaclusters) corresponding to [(Ser8H)n]n+, n = 1, 2, 3. There is a magic number effect favoring formation of the protonated octamer over its homologues and also a strong preference for octamer formation from homochiral serine molecules. Collision-induced dissociation suggests that the protonated octamer is composed of four hydrogen-bonded dimers, stabilized by further extensive hydrogen bonding. Density functional calculations support this model and show that the protonated homochiral octamer is energetically stabilized relative to its possible fragments (dimer plus protonated hexamer, etc). The calculations also show that heterochiral octamers are less stable than homochiral octamers (e.g., the protonated 7:1 cluster is 2.1 kcal/mol less stable than the 8:0 analogue). The implications of these results for the origin of homochirality are discussed.
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Tao WA, Gozzo FC, Cooks RG. Mass spectrometric quantitation of chiral drugs by the kinetic method. Anal Chem 2001; 73:1692-8. [PMID: 11338581 DOI: 10.1021/ac001150v] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel mass spectrometric method for rapid, accurate (2-4% ee) quantitation of chiral drugs is described. Copper(II)-bound complexes of seven model drugs (atenolol, DOPA, ephedrine, pseudoephedrine, isoproterenol, norepinephrine, propranolol) with chiral reference compounds (L-amino acids) are generated by electrospray ionization mass spectrometry. The trimeric complex ions (three chiral ligands--one of the analyte and two of the reference compound) are collisionally activated, and they undergo dissociation by competitive loss of either the neutral reference or the neutral drug molecule. The ratio of the two competitive dissociation rates, viz. the product ion branching ratio, is related via the kinetic method to the enantiomeric composition of the drug mixture. A two-point calibration curve, derived from the kinetic method, allows rapid quantitation of enantiomeric excess of drug mixtures. The chiral sensitivity of the method is such as to allow determination of mixtures with a few percent enantiomeric contamination.
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Gozzo F, Poupaert JH. Xenoestrogens, pollution & health: a critical review. JOURNAL DE PHARMACIE DE BELGIQUE 1998; 53:278-86. [PMID: 9766095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
This review article provides basic information concerning the xenoestrogens (i.e. the sexual hormone mimetic or disruptive compounds) in a perspective willingly selective of the recent literature. In the second part, a hypothetical link between xenoestrogens and disturbances of the central nervous system is considered with respect to steroids more directly involved in the CNS, i.e. the neurosteroids. The data accumulated so far on xenoestrogens present in the environment and their possible competition for membrane-bound neurosteroid receptor sites lend support to the working hypothesis that human behaviour could be affected in the daily life by exposure to chemical pollutants.
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Lamb DC, Kelly DE, Baldwin BC, Gozzo F, Boscott P, Richards WG, Kelly SL. Differential inhibition of Candida albicans CYP51 with azole antifungal stereoisomers. FEMS Microbiol Lett 1997; 149:25-30. [PMID: 9103974 DOI: 10.1111/j.1574-6968.1997.tb10303.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Azole antifungal compounds are important in agriculture and in the treatment of mycotic infection. The target enzyme, sterol 14 alpha-demethylase (CYP51), is inhibited through binding of triazole N-4 to the haem of this P450, as a sixth ligand together with the N-1 substituent groups interacting in some way with the apoprotein. Here we use Saccharomyces cerevisiae expression systems for the target enzyme of Candida albicans to investigate binding of enantiomers of the azole antifungal compounds SCH39304 and tetraconazole. A molecular model produced previously provided qualitative explanations for these differences. Interaction of the azole antifungal aromatic group with Phe-233 or -235 may cause the higher activity for (R)-tetraconazole while inactivity of the (SS)-enantiomer of SCH39304 was predicted to result from incompatibility of the hydrophilic sulfonyl moiety when located into the hydrophobic pocket of the active site.
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Sorrilha AE, Gozzo FC, Pimpim RS, Eberlincor MN. Multiple stage pentaquadrupole mass spectrometry for generation and characterization of gas-phase ionic species. The case of the PyC2H 5 (+·) isomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1996; 7:1126-1137. [PMID: 24203075 DOI: 10.1016/s1044-0305(96)00074-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/1996] [Revised: 06/26/1996] [Accepted: 06/27/1996] [Indexed: 06/02/2023]
Abstract
Eleven isomers with the PyC2H 5 (+·) composition, which include three conventional (1-3) and eight distonic radical cations (4-11), have been generated and in most cases successfully characterized in the gas phase via tandem-in-space multiple-stage pentaquadrupole MS(2) and MS(3) experiments. The three conventional radical cations, that is, the ionized ethylpyridines C2H5-C5H4N(+·) (1-3), were generated via direct 70-eV electron ionization of the neutrals, whereas sequences of chemical ionization and collision-induced dissociation (CID) or mass-selected ion-molecule reactions were used to generate the distonic ions H2C(·)-C5H4N(+)-CH3 (4-6), CH3-C5H4N(+)-CH 2 (·) (7-9), C5H5N(+)-CH2CH 2 (·) (10), and C5H5N(+)-CH(·)-CH3 (11). Unique features of the low-energy (15-eV) CID and ion-molecule reaction chemistry with the diradical oxygen molecule of the isomers were used for their structural characterization. All the ion-molecule reaction products of a mass-selected ion, each associated with its corresponding CID fragments, were collected in a single three-dimensional mass spectrum. Ab initio calculations at the ROMP2/6-31G(d, p)//6-31G(d, p)+ZPE level of theory were performed to estimate the energetics involved in interconversions within the PyC2H5 (+·) system, which provided theoretical support for facile 4⇌7 interconversion evidenced in both CID and ion-molecule reaction experiments. The ab initio spin densities for the a-distonic ions 4-9 and 11 were found to be largely on the methylene or methyne formal radical sites, which thus ruled out substantial odd-spin derealization throughout the neighboring pyridine ring. However, only 8 and 9 (and 10) react extensively with oxygen by radical coupling, hence high spin densities on the radical site of the distonic ions do not necessarily lead to radical coupling reaction with oxygen. The very typical "spatially separated" ab initio charge and spin densities of 4-11 were used to classify them as distonic ions, whereas 1-3 show, as expected, "localized" electronic structures characteristic of conventional radical ions.
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Faraci G, Pennisi AR, Gozzo F, Margaritondo G. Cs bonding at the Cs/GaAs(110) interface. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:3987-3992. [PMID: 9983952 DOI: 10.1103/physrevb.53.3987] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gozzo FC, Eberlin MN. The ionized methylene transfer from the distonic radical cation (+)CH 2-O-CH 2 to heterocyclic compounds. A pentaquadrupole mass spectrometric study. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1995; 6:554-563. [PMID: 24214352 DOI: 10.1016/1044-0305(95)00246-a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/1994] [Revised: 03/14/1995] [Accepted: 03/21/1995] [Indexed: 06/02/2023]
Abstract
Ion-molecule reactions of the mass-selected distonic radical cation (+)CH2-O-CH 2 (·) (1) with several heterocyclic compounds have been investigated by multiple stage mass spectro- metric experiments performed in a pentaquadrupole mass spectrometer. Reactions with pyridine, 2-, 3-, and 4-ethyl, 2-methoxy, and 2-n-propyl pyridine occur mainly by transfer of CH 2 (+·) to the nitrogen, which yields distonic N-methylene-pyridinium radical cations. The MS(3) spectra of these products display very characteristic collision-induced dissociation chemistry, which is greatly affected by the position of the substituent in the pyridine ring. Ortho isomers undergo a δ-cleavage cyclization process induced by the free-radical character of the N-methylene group that yields bicyclic pyridinium cations. On the other hand, extensive CH 2 (+·) transfer followed by rapid hydrogen atom loss, that is, a net CH(+) transfer, occurs not to the heteroatoms, but to the aromatic ring of furan, thiophene, pyrrole, and N-methyl pyrrole. The reaction proceeds through five- to six-membered ring expansion, which yields the pyrilium, thiapyrilium, N-protonated, and N-methylated pyridine cations, respectively, as indicated by MS(3) scans. Ion 1 fails to transfer CH 2 (+·) to tetrahydrofuran, whereas a new α-distonic sulfur ion is formed in reactions with tetrahydrothiophene. Unstable N-methylene distonic ions, likely formed by transfer of CH 2 (+·) to the nitrogen of piperidine and pyrrolidine, undergo rapid fragmentation by loss of the α-NH hydrogen to yield closed-shell immonium cations. The most thermodynamically favorable products are formed in these reactions, as estimated by ab initio calculations at the MP2/6-31G(d,p)//6-31G(d,p) + ZPE level of theory.
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Gozzo F, Berger H, Collins IR, Margaritondo G, Ng W, Ray-Chaudhuri AK, Liang S, Singh S, Cerrina F. Microscopic-scale lateral inhomogeneities of the GaSe-Ge heterojunction energy lineup. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:5024-5027. [PMID: 9979374 DOI: 10.1103/physrevb.51.5024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Stasio GD, Dell'orto T, Gozzo F, Alfe D, Bertolo M, Fontana S, Ciotti MT, Mercanti D, Coluzza C, Perfetti P, Margaritondo G. Imaging photoelectron spectromicroscopy: Biological and materials science applications. ACTA ACUST UNITED AC 1994. [DOI: 10.1080/08940889408261295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Sanjinés R, Rosenfeld D, Gozzo F, Alméras P, Perez L, Lévy F, Margaritondo G, Schreiner WH. ESCA investigation of SnOx films used as gas sensors. SURF INTERFACE ANAL 1994. [DOI: 10.1002/sia.740220181] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gozzo F, Marsi M, Berger H, Margaritondo G, Ottolenghi A, Ray-Chaudhuri AK, Ng W, Liang S, Singh S, Welnak JT, Wallace JP, Capasso C, Cerrina F. Erratum: Microscopic-scale lateral inhomogeneities of the Schottky-barrier-formation process. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:14085. [PMID: 10021609 DOI: 10.1103/physrevb.49.14085.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gozzo F, Marsi M, Berger H, Margaritondo G, Ottolenghi A, Ray-Chaudhuri AK, Ng W, Liang S, Singh S, Welnak JT, Wallace JP, Capasso C, Cerrina F. Microscopic-scale lateral inhomogeneities of the Schottky-barrier-formation process. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:17163-17167. [PMID: 10008322 DOI: 10.1103/physrevb.48.17163] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Perfetti P, Ng W, Ray-Chaudhuri AK, Liang SH, Singh S, Cole RK, Guo ZY, Wallace J, Capasso C, Cerrina F, Mercanti D, Ciotti MT, Gozzo F, Margaritondo G. Scanning photoemission spectromicroscopy of neurons. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1993; 48:1478-1482. [PMID: 9960737 DOI: 10.1103/physreve.48.1478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Hwu Y, Lozzi L, Onellion M, Alméras P, Gozzo F, Lévy F, Berger H, Margaritondo G. Reply to "Lifetime broadening in bulk photoemission spectroscopy". PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:624-625. [PMID: 10006825 DOI: 10.1103/physrevb.48.624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Margaritondo G, Gozzo F, Coluzza C. Band bending at semiconductor interfaces and its effect on photoemission line shapes. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:9907-9909. [PMID: 10005069 DOI: 10.1103/physrevb.47.9907] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Marsi M, Houdré R, Rudra A, Ilegems M, Gozzo F, Coluzza C, Margaritondo G. Artificial band discontinuities at GaAs homojunctions. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:6455-6459. [PMID: 10004612 DOI: 10.1103/physrevb.47.6455] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Coluzza C, Berger H, Alméras P, Gozzo F, Margaritondo G, Indlekofer G, Forro L, Hwu Y. High-resolution tests of low-dimensionality effects in photoemission. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:6625-6629. [PMID: 10004632 DOI: 10.1103/physrevb.47.6625] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ortega J, García-Vidal FJ, Pérez R, Rincón R, Flores F, Coluzza C, Gozzo F, Margaritondo G, Hwu Y, Lozzi L. Early stages of Schottky-barrier formation for Al deposited on GaAs(110). PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:10277-10283. [PMID: 10002872 DOI: 10.1103/physrevb.46.10277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Hwu Y, Lozzi L, Onellion M, Almeras P, Gozzo F, Lévy F, Berger H, Margaritondo G. Photoemission broadening of Fermi-liquid systems, and its relevance to high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 45:5438-5442. [PMID: 10000260 DOI: 10.1103/physrevb.45.5438] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Hwu Y, Lozzi L, Marsi M, Winokur M, Davis P, Onellion M, Berger H, Gozzo F, Lévy F, Margaritondo G. Electronic spectrum of the high-temperature superconducting state. PHYSICAL REVIEW LETTERS 1991; 67:2573-2576. [PMID: 10044460 DOI: 10.1103/physrevlett.67.2573] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Camaggi G, Gozzo F. Photochemical isomerisation derivatives of decafluorocyclohexene and their reactions. ACTA ACUST UNITED AC 1971. [DOI: 10.1039/j39710000925] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Camaggi G, Gozzo F. Synthesis and derivatives of para-bonded isomers of fluoroaromatic compounds. ACTA ACUST UNITED AC 1969. [DOI: 10.1039/j39690000489] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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50
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