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Papers quoted in Current Contents on project 1-08-195

Quoted papers: 17
Other papers: 23
Total: 40

Title: Comparison of the structures of the plant growth hormone indol-3-ylacetic acid, and six of its amino acid conjugates

Authors:: Kojić-Prodić, Biserka; Nigović, Biljana; Horvatić, Davor; Ružić-Toroš, Živa; Magnus, Volker (82051); Duax, William L.; Stezowski, John J.; Bresciani-Pahor, Nevenka

Journal: Acta Crystallographica B
ISSN: 0108-7681
Volume: 47
Year: 1991
Pages: from 107 to 115
Number of references: 34
Language: engleski
Summary: The crystal structures of six biologically active conjugates ofthe plant growth hormone, indole-3-acetic acid (IAA=auxin), withthe amino acids L-alanine (1), alpha-amino-L-butyric acid (2),L-norvaline (3), DL-aspartic acid (4), L-isoleucine (5), anddelta-aminovaleric acid (6) were determined. In these conjugatesthe conformations of the indol-3-ylacetyl moieties are verysimilar to that observed in free IAA, as are the values of bondlengths and intramolecular contact distances within the IAAmoiety. The indole ring system and the C atom of the adjacentmethylene group are coplanar, whereas the -COOH or -CONRresidues, respectively, adopt a folded conformation. The carbonylgroup of the free hormone points towards the indole ring;however, in the amino-acid conjugates it points away from thering system. The orientation of the amino-acid side chains withrespect to the aromatic ring varies in compounds (1) - (6).Consistently, however, only the region of the IAA moiety inimmediate proximity to the -CO group is sterically blocked by theconjugant. The rest of the indole nucleus, which appears toinclude the -NH group, remains potentially available for bindingcompetitively (with free IAA) to proteins such as auxin receptorsand enzymes regulating intracellular levels of growth hormones.
Keywords: Plant growth regulation, plant hormone, auxin, amino acid conjugate, X-ray crystallography, molecular structure, structure-activity relationships, indole-3-acetic acid, N-(indol-3-ylacetyl)-L-alanine, N-(indol-3-ylacetyl)-alpha-amino-L-butyric acid, N-(indol-3-ylacetyl)-L-norvaline, N-(indol-3-ylacetyl)-DL-aspartic acid, N-(indol-3-ylacetyl)-L-isoleucine, N-(indol-3-ylacetyl)-delta-aminovaleric acid

Title: Synthesis of 5-alkylindole-3-acetic acids for use as plant hormone analogues

Authors:: Ilić, Nebojša; Klaić, Branimir; Magnus, Volker (82051); Vikić-Topić, Dražen (71183); Gacs-Baitz, Ester

Journal: Croatica Chemica Acta
ISSN: 0011-1643
Volume: 64
Year: 1991
Pages: from 79 to 88
Number of references: 30
Language: engleski
Summary: 5-n-Alkyl derivatives (9-12) of the plant hormone indole-3-aceticacid were prepared by treating2-(4-alkylphenyl)-hydrazono-4-cyanobutyric acid ethyl esters (1 -4) with a mixture of 35% HCl, 85% phosphoric acid, and pyridine(3:4:1, v/v/v) at 115 degrees C. The corresponding acetonitriles(5-8) were isolated as intermediates and characterized.Spectroscopic evidence indicates that compounds 9 - 12 aresuitable for investigating steric substituent effects on hormonalactivity without major interference of electronic effects.
Keywords: Plant hormone, Fischer indole synthesis, NMR spectroscopy, UV spectroscopy, indole-3-acetic acid, 5-methylindole-3-acetic acid, 5-ethylindole-3-acetic acid, 5-n-propylindole-3-acetic acid, n-butylindole-3-acetic acid, 5-methylindole-3-acetonitrile, 5-ethylindole-3-acetonitrile, 5-n-propylindole-3-acetonitrile, 5-n-butylindole-3-acetonitrile.

Title: Structural studies on 5-(n-alkyl)-substituted derivatives of the plant hormone, indole-3-acetic acid

Authors:: Kojić-Prodić, Biserka; Nigović, Biljana; Tomić, Sanja; Ilić, Nebojša; Magnus, Volker (82051); Giba, Zlatko; Konjević, Radomir; Duax, William L.

Journal: Acta Crystallographica B
ISSN: 0108-7681
Volume: 47
Year: 1991
Pages: from 1010 to 1019
Number of references: 31
Language: engleski
Summary: The molecular structures of IAA and 5-(n-alkyl)indole-3-aceticacids (alkyl = methyl, ethyl, propyl, butyl), as revealed byX-ray crystallography and molecular mechanics calculations, werecompared with growth-promoting activity in the Avena mesocotyltest. In all compounds studied the benzene part of the indolenucleus was typically distorted around C7 (bond length C6-C7 =1.37 A; bond angle C6-C7-C71 = 117.4 degrees, statistical datafor other indole derivatives included). The 5-(n-alkyl) residuewas in an extended zig-zag conformation with the C-alpha-C-betabond pointing away from the aromatic nucleus. In the crystallinestate, the methylene-carboxyl bond was perpendicular to theindole ring plane for 5-methylindole-3-acetic acid (as for IAAitself), and approximately in that plane for the other IAAderivatives studied. Crystal-packing influences appear to beresponsible for this effect. Namely, thepotential-energy-minimized (molecular mechanics) conformations inthe crystal lattice environment corresponded closely to thoseobserved by X-ray analysis while, for the isolated molecules inthe gas phase, perpendicular orientation of the carboxyl groupwas always predominant. The plant-growth-promoting properties ofthe compounds studied were not dramatically different. Thisindicates that a 5-substituent as bulky as n-butyl does notsterically obstruct interaction with the auxin-binding protein(s)involved in the growth response.
Keywords: Plant growth regulation, auxin, structure-activity relationships, X-ray crystallography, molecular mechanics, Avena sativa, mesocotyl test, indole-3-acetic acid, 5-methylindole-3-acetic acid, 5-ethylindole-3-acetic acid, 5-n-propylindole-3-acetic acid, 5-n-butylindole-3-acetic acid.

Title: N-(indol-3-ylacetyl)amino acids as sources of auxin in plant tissue culture

Authors:: Magnus, Volker (82051); Nigović, Biljana; Hangarter, Roger; Good, Norman E.

Journal: Journal of Plant Growth Regulation
ISSN: 0721-7595
Volume: 11
Year: 1992
Pages: from 19 to 28
Number of references: 28
Language: engleski
Summary: N-(Indol-3-ylacetyl) derivatives (IAA conjugates) of aliphaticamino acids with a two- to six-carbon backbone includingalpha-L-amino acids, omega-amino acids, and thealpha,omega-diamino acids ornithine and lysine were prepared,chemically characterized, and tested as sources of auxin in planttissue culture. Stimulation of unorganized growth in Solanumnigrum L. callus and callus induction and developmental effectsin tomato (Lycopersicon esculentum Mill. cv. Marglobe) hypocotylexplants were studied systematically. While the growth-promotingproperties of some of the conjugates were species-dependent,those containing straight-chain two- to four-carbon alpha-L-aminoacid moieties were generally up to 100 times more active thanthose of their five- to six-carbon homologues. Branching of theamino acid back-bone at C-beta and C-gamma has a minor effect,but substitution of H-alpha almost completely blockedgrowth-promoting activity. IAA conjugates of omega-amino acids,were in most cases, nearly as active as those of theiralpha-amino-L-isomers. N(epsilon)-(IAA)lysine was more potentthan its N(alpha)-(IAA)-isomer and N(delta)-(IAA) ornithine; theactivity of N(alpha),N(epsilon)-bis-(IAA)lysine was different intomato and Solanum nigrum. The L-alanine and epsilon-lysineconjugates were also useful for induction of Oenotherea leafcallus and in tomato cell-suspension culture.
Keywords: Plant growth regulation, plant hormone, auxin, amino acid conjugate, plant tissue culture, structure-activity relationships, indole-3-acetic acid, Lycopersicon esculentum, Solanum nigrum, Oenothera sp.

Title: Interaction of free indole 3-acetic acid and its amino acid conjugates in tomato hypocotyl cultures

Authors:: Magnus, Volker (82051); Hangarter, Roger; Good, Norman E.

Journal: Journal of Plant Growth Regulation
ISSN: 0721-7595
Volume: 11
Year: 1992
Pages: from 67 to 75
Number of references: 20
Language: engleski
Summary: The interaction of free indole-3-acetic acid (IAA) and its aminoacid conjugates on growth and development of cultured tomatohypocotyl tissue (Lycopersicon esculentum Mill. cv. Marglobe) wasstudied. In a nutrient medium containing 10 micromol/L ofbenzyladenine, free IAA stimulated shoot and root developmentwith little callus proliferation. In contrast, all IAA-amino acidconjugates tested supported mostly callus growth. Simultaneousapplication of free IAA and its conjugates resulted in theexpression of mixed morphogenetic responses (i.e., both vigorouscallus growth and organogenesis resulted). Growth kinetics andthe effect of temporal exposure of the tissues to the bound andthe free auxin suggest that some IAA-amino acid conjugates mayspecifically influence plant morphogenesis in ways that cannot beeasily explained as simply a function of their slow hydrolysis torelease free IAA.
Keywords: Plant tissue culture, morphogenesis, organogenesis, plant hormone, auxin, amino acid conjugate, interaction of free and conjugated auxin, Lycopersicon esculentum, indole-3-acetic acid, N-(indol-3-ylacetyl)-DL-aspartic acid, N-(indol-3-ylacetyl)-L-alanine, N(epsilon)-(indol-3-ylacetyl)-L-lysine, N(delta)-(indol-3-ylacetyl)-L-ornithine, N-(indol-3-ylacetyl)-L-threonine.

Title: Structural comparison of biologically active and inactive conjugates of alpha-amino acids and the plant growth hormone (auxin) indole-3-acetic acid

Authors:: Kojić-Prodić, Biserka; Nigović, Biljana; Puntarec, Vitomir; Tomić, Sanja; Magnus, Volker (82051)

Journal: Acta Crystallographica B
ISSN: 0108-7681
Volume: 49
Year: 1993
Pages: from 367 to 374
Number of references: 44
Language: engleski
Summary: The crystal structures of the naturally occurring, biologicallyactive conjugate N-(indol-3-ylacetyl)-L-valine (N-(IAA)-L-Val)and the synthetic inactiveN-(indol-3-ylacetyl)-alpha-aminoisobutyric acid(n-(IAA)-alpha-Aib) have been determined. The growth promotingactivity of these compounds is discussed on the basis of theirstereochemical properties. Conformational analysis of theamino-acid side chains has been performed by molecular mechanicsand dynamics, and a comparison has been made with theconformations detected in the solid state. The indole ring systemand the C atom of the adjacent methylene group are coplanarwhereas the CONR residue adopts a folded conformation. In thestructure of N-(IAA)-L-Val the peptide H faces the indole ring.In the structure of N-(IAA)-alpha-Aib the peptide group liesastride the ring plane and is involved in an intramolecularhydrogen bond to the carboxylic group. In both crystalstructures, packing is via N-H...O of the indole N atom and thecarboxylic group, and O-H...O of the carboxylic group and thepeptide O atom.
Keywords: Plant growth regulation, auxin, amino acid conjugate, structure-activity relationships, X-ray crystallography, molecular mechanics, molecular dynamics, conformational analysis, indole-3-acetic acid, N-(indol-3-ylacetyl)-L-valine, N-(indol-3-ylacetyl)-alpha-aminoisobutyric acid.

Title: Synthesis of the beta-D-glucosyl ester of (carbonyl-C-13)-indole-3-acetic acid

Authors:: Jakas, Andreja (192222); Magnus, Volker (82051); Horvat, Štefica (51440); Sandberg, Goran

Journal: Journal of Labelled Compounds and Radiopharmaceuticals
ISSN: 0362-4803
Volume: 33
Year: 1993
Pages: from 933 to 939
Number of references: 23
Language: engleski
Summary: An efficient, operationally simple synthetic approach to1-O-(carbonyl-C-13 -indole-3'-ylacetyl)beta-D-glucopyranose isdescribed. The synthesis was carried out by fusing a fullybenzylated 1-O-glucosylpseudourea intermediate with(carbonyl-C-13)-indole-3-acetic acid, followed by hydrogenolyticremoval of the protective groups.
Keywords: C-13 labeling, indole-3-acetic acid, glucosyl ester

Title: The behaviour of some benzene derivatives on thin layers of aluminum oxide - comparation with plain and Fe(III)impregnated silica gel

Authors:: Kveder, Sergije (25070); Iskrić, Sonja (17071); Zambeli, Z; Hadžija, Olga (15043)

Journal: Journal of Liquid Chromatography
ISSN: 0148-3919
Volume: 14
Year: 1991
Pages: from 3277 to 3282
Number of references: 10
Language: engleski
Summary: The behavior of some carboxy and hydroxy benzene derivativesrelated to humic material was examined by thin layerchromatography using aluminum oxide as the support and water asthe developer. Their RF-values are compared with those on plainand Fe(III)-impregnated silica gel plates.
Keywords: Thin-layer chromatography, adsorption by soil, humic material, aluminum oxide, silica gel, impregnation with Fe(III), benzenecarboxylic acid, benzenecarboxaldehyde, hydroxybenzene.

Title: Behavior of some benzene derivatives on progressively dried Fe(III)-impregnated silica gel plates

Authors:: Kveder, Sergije (25070); Iskrić, Sonja (17071); Zambeli, N; Hadžija, Olga (15043)

Journal: Journal of Liquid Chromatography
ISSN: 0148-3919
Volume: 15
Year: 1992
Pages: from 1719 to 1727
Number of references: 10
Language: engleski
Summary: The influence of progressive drying on Fe(III)-hydroxy-oxidesupport on the behavior of hydroxy- and carboxy-benzenederivatives in thin-layer chromatography was investigated. Theresults show that different complexes are formed depending on thekind of substances and/or conditions applied.
Keywords: Thin-layer chromatography, adsorption by soil, humic materijal, impregnated silica gel, Fe(III)oxide-hydrate, degree of hydratation, benzenecarboxylic acid, hydroxybenzene.

Title: Synthesis and conformational analysis of 2-(indol-3-yl)-ethyl alpha-L-arabinopyranoside and its 2,3,4-tri-O-acetyl derivative

Authors:: Tomić, Sanja; v. Eijck, Boue; Kroon, Jan; Kojić-Prodić, Biserka; Laćan, Goran (58844); Magnus, Volker (82051); Duddeck, Helmut; Hiegemann, Monika

Journal: Carbohydrate Research
ISSN: 0008-6215
Volume: 259
Year: 1994
Pages: from 175 to 190
Number of references: 40
Language: engleski
Summary: 2-(indol-3-yl)ethyl-alpha-L-arabinopyranoside (1) was prepared by condensation of the aglycon alcohol with 2,3,4-O-acetyl-beta-L-arabinopyranosyl bromide, followed by deacetylation. Structure and conformation of the crystalline per-O-acetetylated derivative were determined by X-ray diffraction, NMR, and computational methods (molecular mechanics and dynamics). The latter methods permitted extrapolation to the free glycoside 1 which does not crystallize. In all observed conformes, the indole ring was near-perpendicular to the rest of the molecule, which may be one of the prerequisites for bioactivity.
Keywords: Glycoside, molecular structure, X-ray structure analysis, nuclear Overhauser effect, molecular mechanics, molecular dynamics, conformational analysis, conformation of bioactive molecules, 2-(indol-3-yl)ethyl alpha-L-arabinopyranoside, 2-(indol-3-yl)ethanol.

Title: (E) and (Z)-beta-Fluoromethylene-m-tyrosines: resolution and determination of configuration

Authors:: Laćan, Goran (58844); Satyamurthy, Nagichettiar; Barrio, Jorge R.

Journal: Tetrahedron Asymmetry
Number: 2
ISSN: 0957-4166
Volume: 6
Year: 1995
Pages: from 525 to 535
Number of references: 40
Language: engleski
Summary: The geometrical isomers of beta-fluoromethylene-m-tyrosine (E and Z) were prepared and the R and S enantiomers of the biologically active (E)-isomer were separated with an enantiomeric excess more 95% by kinetic resolution of the racemic mixture using the enzyme alpha-chymotrypsin. The enantiomers of the (Z)-isomer were obtained by and acid catalyzed isomerization reaction. The absolute configurations of the isolated isomers were determined based on their CD spectral characteristic, chiral HPLC behavior, and X-ray crystallography.
Keywords: beta-fluoromethylene-m-tyrosine, kinetic resolution of enantiomers, alpha-chymotrypsin, CD spectrum, chiral HPLC, X-ray chrystallography

Title: (Z)-beta-Fluoromethylene-m-tyrosine: synthesis, crystal structure and fluorination

Authors:: Laćan, Goran (58844); Satyamurthy, Nagichettiar; Barrio, Jorge R.

Journal: Journal of Fluorine Chemistry
ISSN: 0022-1139
Volume: 99
Year: 1995
Pages: from 1 to 999
Number of references: 27
Language: engleski
Summary: (Z)-beta-fluoromethylene-m-tyrosine (1) was prepared by acid hydrolysis of ethyl 2-trifluoroacetylamino-3-(3-methoxyphenyl)-4-fluoro-3-butenoate and its structure was established by single crystal X-ray diffraction analysis. Fluorination of the amino acid 1 with acetyl hypofluorite yielded a mixture of products containing fluorine substituted on the ring as well as added across the vinylic double bond.
Keywords: mechanism-based inhibition, fluoromethylene amino acid, monoamine oxidase, crystal structure

Title: Fluorination of (E)-beta-(fluoromethylene)-m-tyrosine: regioselective synthesis of 4-fluoro-(E)-beta-(fluoromethylene)-m-tyrosine

Authors:: Laćan, Goran (58844); Satyamurthy, Nagichettiar; Barrio, Jorge R.

Journal: Journal of Organic Chemistry
Number: 1
ISSN: 0022-3263
Volume: 60
Year: 1995
Pages: from 227 to 234
Number of references: 31
Language: engleski
Summary: Fluorination of (R)- and (S)-(E)-beta-(fluoromethylene)-m-tyrosine by acetyl hypofluorite yielded a mixture of the corresponding 2-fluoro-, 6-fluoro-, 4-fluoro-, and 2,6-difluoro-derivatives along with a pair of diastereomeric products of addition across the vinylic double bond. A regioselective synthesis of 4-fluoro-(E)-beta-(fluoromethylene)-m-tyrosine was also developed based on a fluorodestannylation reaction. The products were characterized by NMR and mass spectroscopies and, for the key compounds, by X-ray crystallographic analysis.
Keywords: (S)-(E)-beta-(fluoromethylene)-m-tyrosine, 4-fluoro-(E)-beta-(fluoromethylene)-m-tyrosine, fluorination with acetyl hypofluorite, fluorodestannylation, nuclear magnetic resonance, mass spectroscopy, X-ray crystallography

Title: Quantitative structure-activity relationships for N-(indol-3-ylacetyl)amino acids used as sources of auxin in plant tissue culture

Authors:: Šoškić, Milan; Klaić, Branimir; Magnus, Volker (82051); Sabljić, Aleksandar

Journal: Plant Growth Regulation
ISSN: 0167-6903
Volume: 16
Year: 1995
Pages: from 141 to 152
Number of references: 40
Language: engleski
Summary: The methods of quantitative structure-activity relationship analysis were applied to N-(indol-3-ylacetyl)amino acids tested as promoters of unorganized callus growth in cultures derived from sybean and from Solanum nigrum L. Two types of statistical models were developed describing molecular structure: (a) by molecular connectivity indices or (b) by experimentally determined biochemical constants of which lipophilicity and resistance to peroxidases were found to be most important.
Keywords: amino acid conjugate, indole-3-acetic acid, plant growth regulation, plant tissue culture, quantitative structure-activity relationship, QSAR analysis

Title: Synthesis and conformatinal analysis of the plant hormone (auxin= related 2-(indol-3-yl)ethyl and 2-phenylethyl beta-D-xylopyranosides and their 2,3,4-tri-O-acetyl derivatives

Authors:: Tomić, Sanja; van Eijck, Bouke P.; Kojić-Prodić, Biserka; Kroon, Jan; Magnus, Volker (82051); Nigović, Biljana; Laćan, Goran (58844); Ilić, Nebojša; Duddeck, Helmut; Hiegemann, Monika

Journal: Carbohydrate Research
ISSN: 0008-6215
Volume: 270
Year: 1995
Pages: from 11 to 32
Number of references: 52
Language: engleski
Summary: The synthesis, structure analysis by X-ray diffraction and NMR spectroscopy, as well as molecular mechanics and dynamics of D-xylopyranose conjugates of 2-(indol-3-yl)ethanol and 2-phenylethanol are described. The beta-D-xylopyranose rings are in the 4C1 chair conformation. The results of theoretical conformational analyses are compared with the data obtained by empirical measurements in the solid state and in solution.
Keywords: auxin, xylopyranoside, X-ray diffraction, NMR spectroscopy, nuclear Overhauser effect, molecular mechanics, molecular dynamics

Title: Effect of halogen substitution of indole-3-acetic acid on biological activity in pea fruit

Authors:: Reinecke, Dennis M.; Ozga, Jocelyn A.; Magnus, Volker (82051)

Journal: Phytochemistry
ISSN: 0031-9422
Volume: 40
Year: 1995
Pages: from 00 to 00
Number of references: 32
Language: engleski
Summary: Pea fruits contain the auxins indole-3-acetic acid (IAA) and 4-chloroindole-3-acetic acid (4-Cl-IAA). Such fruits grow poorly and subsequently abscise when seeds are removed, but develop almost normally when 4-Cl-IAA is subsequently applied. 5-, 6-, and 7-chloro-substituted IAAs were considerably less affective, and the corresonding fluoro analogues were inactive or inhibitory. Unsubstituted IAA had no effect, in this system.
Keywords: Pisum sativum, pea pericarp, auxin, indole-3-acetic acid, 4-chloroindole-3-acetic acid, halogenated IAA analog

Title: Behaviour of humic acids on Fe(III)-impregnated silica gel compared with model substances

Authors:: Iskrić, Sonja (17071); Hadžija, Olga (15043); Kveder, Sergije (25070)

Journal: Journal of Liquid Chromatography
Number: 7
ISSN: 0148-3919
Volume: 17
Year: 1994
Pages: from 1653 to 1657
Number of references: 7
Language: engleski
Summary: The behavior of humic acids under the conditions of thin-layer chromatography on Fe(III)-impregnated silica gel with tap water as the developer was investigated. Compounds having similar functional groups as the humic material were compard and conclusions extended to natural conditions were drawn.
Keywords: humic acid, silica gel, impregnation with Fe(III), soil, cation mobility

Title:

Authors:: Nigović, Biljana; Kojić-Prodić, Biserka; Tomić, Sanja; Ilić, Nebojša; Magnus, Volker (82051)

Number: ecte
Volume: Coll
Year: 1991
Pages: from 306 to 306
Number of references: 103
Language: engleski


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