Structure of the Z isomer of 5-[(4-methoxyphenyl)methylene]imidazolidine-2,4-dione

Drew, Michael G. B.; Mok, K. F.; Ang, K. P.; Tan, S. F.

doi:10.1107/s0108270187094289

Cited by 7 publications

(1 citation statement)

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“…(1) Stabilization of the Trans Isomer. On the basis of smallmolecule crystal structures (44,45), quantum mechanical calculations (46), and recent NMR results (12), the preferred conformation of the chromophore is thought to be planar with the p-hydroxybenzyl group in the cis conformation. This preference for the cis over the trans isomer can be attributed to a steric collision between the O2 and Cδ2-H atoms in the trans form (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,

et al. 2005

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When the nonfluorescent chromoprotein asFP595 from Anemonia sulcata is subjected to sufficiently intense illumination near the absorbance maximum (lambda(abs)(max) = 568 nm), it undergoes a remarkable transition, termed "kindling", to a long-lived fluorescent state (lambda(em)(max) = 595 nm). In the dark recovery phase, the kindled state relaxes thermally on a time scale of seconds or can instantly be reverted upon illumination at 450 nm. The kindling phenomenon is enhanced by the Ala143 --> Gly point mutation, which slows the dark recovery time constant to 100 s at room temperature and increases the fluorescence quantum yield. To investigate the chemical nature of the chromophore and the possible role of chromophore isomerization in the kindling phenomenon, we determined the crystal structure of the "kindling fluorescent protein" asFP595-A143G (KFP) in the dark-adapted state at 1.38 A resolution and 100 K. The chromophore, derived from the Met63-Tyr64-Gly65 tripeptide, closely resembles that of the nonfluorescent chromoprotein Rtms5 in that the configuration is trans about the methylene bridge and there is substantial distortion from planarity. Unlike in Rtms5, in the native protein the polypeptide backbone is cleaved between Cys62 and Met63. The size and shape of the chromophore pocket suggest that the cis isomer of the chromophore could also be accommodated. Within the pocket, partially disordered His197 displays two conformations, which may constitute a binary switch that stabilizes different chromophore configurations. The energy barrier for thermal relaxation was found by Arrhenius plot analysis to be approximately 71 kJ/mol, somewhat higher than the value of approximately 55 kJ/mol observed for cis-trans isomerization of a model chromophore in solution.

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Section: Discussionmentioning

confidence: 99%

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,

et al. 2005

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NMR spectroscopic study of configurations and conformations of 5‐pyridylmethylenehydantoins

Tan

Ang

How

1990

J of Physical Organic Chem

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Nine 5‐pyridylmethylenehydantoins were prepared. Each of the 1‐methyl‐substitute compounds was obtained in two stereoisomeric forms. Only one form of each of the 3‐methyl‐substituted and N‐unsubstituted compounds was obtained directly from synthesis but could be partially converted into the other stereoisomer photochemically. The Z/E configurations and the conformational relationship between the pyridine and hydantoin rings were studied by 1H and 13C NMR spectroscopy, including variable‐temperature 1H NMR. The existence of NH…︁N or CH…︁N interactions and the possibility of tautomerism are suggested for some of the compounds. The Z‐isomers of compounds with 2‐ or 3‐pyridyl rings prefer an s‐cis conformation whereas the E‐isomers prefer an s‐trans conformation.

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Intermolecular and intramolecular hydrogen bonding in 5‐pyridylmethylenehydantoins: IR and NMR study

Tan

Ang

How

1991

J of Physical Organic Chem

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The patterns of the NH stretching vibrations in the solid‐state IR spectra of a series of 5‐pyridylmethylenehydantoins revealed the presence of various modes of hydrogen bonding: intermolecular NH&4nldr; &4nldr;OC and intermolecular or intramolecular NH&4nldr; ‥‥N(py). These variations are related to the orientation of the pyridyl nitrogen and to stereochemistry. A distinction between intramolecularly and intermolecularly hydrogen‐bonded compounds was also provided by comparison of the 1H NMR spectra in (CD3)2SO and in CDCl3.

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Structure of the Z isomer of 5-[(4-methoxyphenyl)methylene]imidazolidine-2,4-dione

Cited by 7 publications

References 1 publication

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,

NMR spectroscopic study of configurations and conformations of 5‐pyridylmethylenehydantoins

Intermolecular and intramolecular hydrogen bonding in 5‐pyridylmethylenehydantoins: IR and NMR study

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Structure of the Z isomer of 5-[(4-methoxyphenyl)methylene]imidazolidine-2,4-dione

Cited by 7 publications

References 1 publication

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution,

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution,

NMR spectroscopic study of configurations and conformations of 5‐pyridylmethylenehydantoins

Intermolecular and intramolecular hydrogen bonding in 5‐pyridylmethylenehydantoins: IR and NMR study

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Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,

Kindling Fluorescent Protein fromAnemonia sulcata: Dark-State Structure at 1.38 Å Resolution^,