Neutron diffraction study of <scp>L</scp>-phenylalanine hydrochloride

Al-Karaghouli, A. R.; Koetzle, T. F.

doi:10.1107/s0567740875007807

Cited by 59 publications

(34 citation statements)

References 10 publications

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“…The patterns were in good agreement with those calculated from the literatures, from which the space groups of L-phenylalanine hydrochloride and L-valine hydrochloride were confirmed to be P2 1 2 1 2 1 (Z = 4, a = 27.763 Å, b = 7.059 Å, c = 5.380 Å) [13] and P2 1 (Z = 2, a = 10.382 Å, b = 7.066 Å, c = 5.440 Å, β = 91.40 • ), [14] respectively.…”

Section: Methodssupporting

confidence: 79%

A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

Yamada¹,

Shimizu²,

Ohki³

et al. 2008

Magnetic Reson in Chemistry

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We have presented an experimental investigation of the oxygen-17 chemical shielding (CS) and electric-field-gradient (EFG) tensors for alpha-COOH groups in polycrystalline amino acid hydrochlorides. The 17O CS and EFG tensors including the relative orientations between the two NMR tensors are determined in [17O]-L-phenylalanine hydrochloride and [17O]-L-valine hydrochloride by the analysis of the 17O magic-angle-spinning (MAS) and stationary NMR spectra obtained at 9.4, 11.7, 16.4, and 21.8 T. The quadrupole coupling constants (CQ) and the span of the CS tensors are found to be 8.41-8.55 MHz and 7.35-7.41MHz, and 548-570 ppm and 225-231 ppm, for carbonyl and hydroxyl oxygen atoms, respectively. Extensive quantum chemical calculations using density functional theory (DFT) have been also carried out for a hydrogen-bonding model. It is demonstrated that the behavior of the dependence of hydrogen-bond distances on 17O NMR tensors for the halogen ions is different from those for the water molecule.

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Section: Methodssupporting

confidence: 79%

A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

Yamada¹,

Shimizu²,

Ohki³

et al. 2008

Magnetic Reson in Chemistry

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“…It should be noted here which atom can be the acceptor of the third hydrogen bond of the amino nitrogen atom N1. As listed in Table 4, although 02 [3] is much closer to Nl than is O1S [1], the direction of N1-02 is more deviated from N1-H"Nl than that of Nl-O1S. Furthermore, since the distance O 1 S-H"N 1 is slightly shorter than 02-H"N 1, O1S [1] seems to be a more favorable candidate for the acceptor of the hydrogen bond from N1.…”

mentioning

confidence: 99%

“…Furthermore, since the distance O 1 S-H"N 1 is slightly shorter than 02-H"N 1, O1S [1] seems to be a more favorable candidate for the acceptor of the hydrogen bond from N1. 02 [3] lies on the basal plane of the electron deficient pyramid formed by N 1 and its three hydrogen atoms.…”

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confidence: 99%

The Crystal Structure of Di-L-phenylalanine Sulfate Monohydrate

et al. 1992

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“…2. Some selected torsion angles, together with those of Phe in its HCl crystal, 16) are given in Table 2. 3-FluoroPhe, 2,4,5-and 3,4,5-trifluoroPhe: Some notable conformational/structural similarities could be observed in these crystal structures.…”

Section: Resultsmentioning

confidence: 99%

“…Comparison with Phe: As compared with the molecular packing of Phe in the HCl crystal, 16) the most notable feature of fluoroPhes is that their crystals consist of two different conformers. This could be due to the additive intermolecular nonbonded interactions in which fluorine atoms participate.…”

Section: Resultsmentioning

confidence: 99%

Aggregation Feature of Fluorine-Substituted Benzene Rings and Intermolecular C-H...F Interaction: Crystal Structure Analyses of Mono- and Trifluoro-L-phenylalanines

Kishima

Minoura

et al. 2003

CHEMICAL & PHARMACEUTICAL BULLETIN

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It is well documented that noncovalent aromatic-aromatic interactions are important in determining the molecular conformation, stability and activity of biological macromolecules. 1,2) In globular proteins, the close interactions between the aromatic amino acids Phe, Tyr and Trp often form a part of a hydrophobic pocket to bind an aromatic substrate. [3][4][5] As for the aromatic interaction of phenylalanine (Phe) residues in proteins, either an off-center displaced face-toface or a T-shaped edge-to-face structure has been considered as the preferred orientation since it is nearly isoenergetic.6) In the latter structure, the acidic C-H group on the benzene ring acts as a weak hydrogen-bonding donor and the p-electron on the ring acts as an acceptor. This means that the benzene ring can serve as a pocket accepting the cationic molecule through the cation … p interaction.2,7) On the other hand, the benzene ring in which H atoms are substituted by fluorine atoms could serve as an anion-acceptor through the anion … p interaction, 2,8) based on the crystal structure of C 6 H 6 · C 6 F 6 complex at 30 K. 9) Thus, the benzene ring can be said to form different noncovalent interactions by replacing the hydrogen atoms with other atoms, information on the association pattern of heteroatom-substituted benzene rings in the crystal structure is useful for designing an acceptor molecule to recognize a specified aromatic molecule.Herein, we report the crystal structures of four kinds of fluorophenylalanines (3-fluoro-, 4-fluoro-, 2,4,5-trifluoro-, and 3,4,5-trifluoroPhes). The observed structural features make it clear how the noncovalent interaction of benzene rings is affected by the substituted position and number of fluorine atoms. Especially, we focus on (i) how the acidity of benzene C-H proton is activated by the substitution of fluorine atom, and (ii) which donor group (benzene C-H or amino N-H) participates preferentially in the interaction with the electronegative fluorine atom. The present results are of interest to learn why thrombin receptor-derived peptide SFLLRNP (Ser-Phe-Leu-Leu-Arg-Asn-Pro) is able to activate the activity several fold by the substitution of para-fluoroPhe for Phe-2.10) The atomic numbering of the four kinds of fluorophenyl-alanines used in this work is given in Fig. 1. ExperimentalMaterial Three kinds of monofluoro-L-Phe were purchased from Wako Pure Chemical (Tokyo). Di-and trifluoroPhes were prepared according to the previously reports.11,12) The purities were verified by analytical RP-HPLC.X-Ray Crystal Analysis Among various attempts to crystallize a series of mono-, di-, and tri-fluoroPhes, single crystals of 3-and 4-monofluoro and 2,4,5-and 3,4,5-trifluoroPhes were obtained from the slow evaporation of aqueous ethanol or methanol solution at room temperature in the form of transparent needles. The X-ray measurements were made on a Rigaku AFC-5 diffractometer with graphite-monochromated CuKa radiation (lϭ 1.5418 Å) using a w-2q scan mode for 3-fluoroPhe and a Brucker SMART APEX CCD diffr...

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Neutron diffraction study of L-phenylalanine hydrochloride

Abstract: A neutron diffraction study of the amino acid salt L-phenylalanine.HC1 (C9HI2NO+CI -) has been carried out. Space group P2t2121; a=27.763 (17), b=7.059 (4), c= 5.380 (5)

Cited by 59 publications

References 10 publications

A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

The Crystal Structure of Di-L-phenylalanine Sulfate Monohydrate

Aggregation Feature of Fluorine-Substituted Benzene Rings and Intermolecular C-H...F Interaction: Crystal Structure Analyses of Mono- and Trifluoro-L-phenylalanines

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Neutron diffraction study of L-phenylalanine hydrochloride

Abstract: A neutron diffraction study of the amino acid salt L-phenylalanine.HC1 (C9HI2NO+CI -) has been carried out. Space group P2t2121; a=27.763 (17), b=7.059 (4), c= 5.380 (5)

Cited by 59 publications

References 10 publications

A solid‐state 17O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

A solid‐state 17O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

The Crystal Structure of Di-L-phenylalanine Sulfate Monohydrate

Aggregation Feature of Fluorine-Substituted Benzene Rings and Intermolecular C-H...F Interaction: Crystal Structure Analyses of Mono- and Trifluoro-L-phenylalanines

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A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides

A solid‐state ¹⁷O NMR study of L ‐phenylalanine and L ‐valine hydrochlorides