scholarly journals Crystal structure of an aromatic ring opening dioxygenase LigAB, a protocatechuate 4,5-dioxygenase, under aerobic conditions

Structure ◽  
1999 ◽  
Vol 7 (8) ◽  
pp. 953-965 ◽  
Author(s):  
Keisuke Sugimoto ◽  
Toshiya Senda ◽  
Hisae Aoshima ◽  
Eiji Masai ◽  
Masao Fukuda ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Aromatic Ring ◽  
Ring Opening ◽  
Aerobic Conditions

4-(Acetylaminomethyl)-1-methylpyridinium iodide

2007 ◽  
Vol 63 (11) ◽  
pp. o4278-o4278
Author(s):  
Alexandra M. Z. Slawin ◽  
William T. A. Harrison
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Aromatic Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
Compound C ◽  
Acetyl Group

In the title compound, C9H13N2O+·I−, the dihedral angle between the aromatic ring and the N-acetyl group is 73.93 (8)°. In the crystal structure, the cation and anion interact by way of an N—H...I hydrogen bond.

Effect of the support acidity on the aromatic ring-opening of pyrolysis gasoline over Pt/HZSM-5 catalysts

2009 ◽  
Vol 143 (1-2) ◽  
pp. 115-119 ◽  
Author(s):  
Pedro Castaño ◽  
Alazne Gutiérrez ◽  
Inés Villanueva ◽  
Barbara Pawelec ◽  
Javier Bilbao ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Ring Opening ◽  
Pyrolysis Gasoline ◽  
Effect Of The Support

1-Benzoyl-3-(4-chlorophenyl)thiourea

2006 ◽  
Vol 62 (4) ◽  
pp. o1419-o1420 ◽  
Author(s):  
M. Khawar Rauf ◽  
Amin Badshah ◽  
Ulrich Flörke ◽  
Aamer Saeed
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Aromatic Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
Crystal Packing ◽  
Compound C

In the crystal structure of the title compound, C14H11ClN2OS, the dihedral angle between the two aromatic ring planes is 43.93 (6)°. The crystal packing shows dimers formed by intermolecular N—H...S hydrogen bonds which are stacked along [100].

The crystal structure of Proteus vulgaris tryptophan indole-lyase complexed with oxindolyl-L-alanine: implications for the reaction mechanism

2018 ◽  
Vol 74 (8) ◽  
pp. 748-759
Author(s):  
Robert S. Phillips ◽  
Adriaan A. Buisman ◽  
Sarah Choi ◽  
Anusha Hussaini ◽  
Zachary A. Wood
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Aromatic Ring ◽  
Active Site ◽  
Enzymatic Reaction ◽  
Proteus Vulgaris ◽  
Bacterial Enzyme ◽  
Small Domain ◽  
Out Of Plane ◽  
Reversible Formation

Tryptophan indole-lyase (TIL) is a bacterial enzyme which catalyzes the reversible formation of indole and ammonium pyruvate from L-tryptophan. Oxindolyl-L-alanine (OIA) is an inhibitor of TIL, with a K i value of about 5 µM. The crystal structure of the complex of Proteus vulgaris TIL with OIA has now been determined at 2.1 Å resolution. The ligand forms a closed quinonoid complex with the pyridoxal 5′-phosphate (PLP) cofactor. The small domain rotates about 10° to close the active site, bringing His458 into position to donate a hydrogen bond to Asp133, which also accepts a hydrogen bond from the heterocyclic NH of the inhibitor. This brings Phe37 and Phe459 into van der Waals contact with the aromatic ring of OIA. Mutation of the homologous Phe464 in Escherichia coli TIL to Ala results in a 500-fold decrease in k cat/K m for L-tryptophan, with less effect on the reaction of other nonphysiological β-elimination substrates. Stopped-flow kinetic experiments of F464A TIL show that the mutation has no effect on the formation of quinonoid intermediates. An aminoacrylate intermediate is observed in the reaction of F464A TIL with S-ethyl-L-cysteine and benzimidazole. A model of the L-tryptophan quinonoid complex with PLP in the active site of P. vulgaris TIL shows that there would be a severe clash of Phe459 (∼1.5 Å apart) and Phe37 (∼2 Å apart) with the benzene ring of the substrate. It is proposed that this creates distortion of the substrate aromatic ring out of plane and moves the substrate upwards on the reaction coordinate towards the transition state, thus reducing the activation energy and accelerating the enzymatic reaction.

Chemical transformation of 1,2-oxazinochlorin derivatives: synthesis and X-ray crystal structure of a novel porphyrin-porphyrin dimer with a condensed cyclohexane ring

2007 ◽  
Vol 11 (01) ◽  
pp. 31-41 ◽  
Author(s):  
Yuliya V. Morozova ◽  
Dmitry V. Yashunsky ◽  
Zoya A. Starikova ◽  
Gelii V. Ponomarev
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Chemical Transformation ◽  
Trifluoroacetic Acid ◽  
Ring Opening ◽  
Nickel Complex ◽  
Cyclohexane Ring ◽  
X Ray ◽  
Reagent Treatment ◽  
Porphyrin Dimer

Base-assisted ring opening in 1,2-oxazinochlorin derivatives led selectively to the corresponding meso-cyanohydroxychlorin derivatives. The latter could then undergo acid-mediated carbocation formation followed by nucleophilic treatment to give different products, depending on the nature of the nucleophile reagent. Treatment of (E)- and/or (Z)-2-ethylidene-3-hydroxy-5-cyano-3,7,8,12,13,17,18-heptaethylchlorin nickel complex with a mixture of 5% trifluoroacetic acid and dichloromethane yielded a novel type porphyrin-porphyrin dimer with a condensed cyclohexane ring in an almost quantitative yield. The structure of this dimer was determined by single crystal X-ray analysis.

scholarly journals Crystal structure of 1-[(2,4,6-triisopropylphenyl)sulfonyl]aziridine

2015 ◽  
Vol 71 (7) ◽  
pp. o438-o439 ◽  
Author(s):  
Lena Knauer ◽  
Christopher Golz ◽  
Carsten Strohmann
Keyword(s):  
Crystal Structure ◽  
Aromatic Ring ◽  
Title Compound ◽  
Ring Plane ◽  
Isopropyl Group ◽  
Compound C ◽  
Distorted Geometry

The title compound, C17H27NO2S, exhibits a distorted geometry of the aromatic ring with elongated bonds at theipso-C atom. The S atom deviates from the aromatic ring plane by 0.393 (4) Å. Similar to this, the adjacent isopropyl groups are bent out of the aromatic ring plane by −0.125 (4) and −0.154 (4) Å. Even the distant isopropyl group inpara-position to the sulfonyl moiety shows a slight deviation from the ring plane of 0.111 (5) Å. These distortions, which are caused by the bulky substituents, can also be observed in related sulfonylaziridine structures.

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