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Results for “Spectrum Analysis, Raman”

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PubMed2001

Elucidation of protein-lipid interactions in a lysozyme-corn oil system by Fourier transform Raman spectroscopy.

Lysozyme (25% in D2O, corn oil, and their emulsions (10% w/w oil/D2O solution) were examined by Fourier transform Raman spectroscopy. Emulsions showed three layers, namely, top oil, middle cream, and bottom aqueous layers. Raman spectral analysis revealed hydrophobic interactions involving both protein and lipid components. Compared to lysozyme in D2O, the difference spectrum obtained after subtraction of oil from the cream layer spectrum showed reduced intensity of tryptophan bands at 760, 1013, 1340, and 1360 cm(-)(1), reduced intensity ratio of the tyrosine doublet at 850 and 830 cm(-)(1), and increased intensity of the C-H bending band at 1455 cm(-)(1). Compared to corn oil, the difference spectrum after subtraction of lysozyme from the cream layer spectrum indicated decreased intensity at 2855 cm(-)(1) (lipid CH(2) symmetric stretch) and 3011 cm(-)(1) (unsaturated fatty acid hydrocarbon chain =C-H stretch) and a higher intensity ratio of the C-H stretching band at 2900 cm(-)(1) to bands at 2885 and 2933 cm(-)(1). Spectra of the top and bottom layers resembled corn oil and lysozyme, respectively, except for changes in the D2O band. Raman spectroscopy can be used to detect structural changes in proteins, lipids, and D2O due to protein-lipid interactions.

Corn Oil↗
PubMed2006

[Raman scattering study of DL-alanine].

Studies of Raman vibration spectra are useful to obtaining information on biomolecular crystals. The cell dimensions of the L- and DL-alanine crystals are nearly identical, and both structures belong to the orthorhombic system, but the space group is P2(1) 2(1) 2(1) for the L-isomer, and Pna2(1) for the racemate crystal. The Raman spectrum of L-alanine has been measured by many authors. The present work is focusing on the Raman scattering study of DL-alanine powder. Based on the analysis of the differences between DL-alanine and L-alanine Raman spectra, the authors obtained indispensable information on hydrogen bond and the motion of the molecular conformation in alanine crystals.

Alanine↗
PubMed2005

Stopped-flow spectrophotometric and resonance Raman analyses of aldoxime dehydratase involved in carbon-nitrogen triple bond synthesis.

On stopped-flow analysis of aliphatic aldoxime dehydratase (OxdA), a novel hemoprotein, a spectrum derived from a reaction intermediate was detected on mixing ferrous OxdA with butyraldoxime; it gradually changed into that of ferrous OxdA with an isosbestic point at 421 nm. The spectral change on the addition of butyraldoxime to the ferrous H320A mutant showed the formation of a substrate-coordinated mutant, the absorption spectrum of which closely resembled that of the above intermediate. These observations and the resonance Raman investigation revealed that the substrate actually binds to the heme in OxdA, forming a hexa-coordinate low-spin heme.

Carbon↗
PubMed2001

Excitation wavelength-dependent changes in Raman spectra of whole blood and hemoglobin: comparison of the spectra with 514.5-, 720-, and 1064-nm excitation.

Raman spectra of whole blood and oxy-hemoglobin (Hb) were measured under the same conditions with visible (514.5 nm) and near-infrared (NIR; 720 and 1064 nm) excitation, and the obtained spectra were compared in detail. The Raman spectrum of blood excited with visible light is dominated by very intense bands due to carotenoids, so that it was difficult to obtain information about Hb from the spectrum. The Raman spectra of whole blood and oxy-Hb excited with 720 nm light are very close to each other; both spectra are essentially Raman spectra of the heme chromophore that is preresonant with Q bands. Qualitative spectral analysis including band assignment and investigation of nature of resonance effect were carried out for the Raman spectra with 720 nm excitation. The spectra of whole blood and oxy-Hb excited with 1064 nm light contain contributions from nonresonance Raman spectra of the heme chromophore and Raman spectra of proteins. The 1064 nm excited spectra of blood and oxy-Hb are similar to each other but different in some features. For example, bands due to protein appear stronger in the spectrum of whole blood than in that of oxy-Hb which does not contain protein except globin part. The comparison between the 514.5, 720, and 1064 nm excited Raman spectra reveal that the excitation wavelength of 720 nm is more practical than that of visible light and 1064 nm in the Raman analysis of Hb, such as oxygenation, specially in situ measurement.

Adult↗
PubMed2004

Vibrational frequencies and structural determination of tetraiododiphosphine.

The normal mode frequencies and corresponding vibrational assignments of of tetraiododiphosphine in C2h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of six types of motion (P-I stretch, P-P stretch, PI2 scissors, PI2 twist, PI2 wag, and PI2 rock) predicted by a group theoretical analysis. Computed vibrational frequencies are with IR and Raman spectra available in the literature, and uniform scaling factors are derived. Theoretical IR and Raman intensities are reported.

Iodides↗
PubMed2004

[The analysis of Gynostemma pentaphyllum (Thunb) Makino for Chinese crude drug by FTIR and FT-Raman].

The Gynostemma pentaphyllum is an important plant for Chinese crude drug. To qualitatively analyse the Gynostemma pentaphyllum (Thunb) Makino, FTIR and FT-Raman were used to identify the contents of it. The results show, that the trough of each absorption in the picture of FTIR spectrum and the characteristic wave crest of each dispersion in the picture of FT-Raman spectrum had parallelism at their position, their relation pairs with each other. This is useful for the further on-line quantitative analysis and quality control of the Gynostemma pentaphyllum (Thunb) Makino. This approach provide a quickly and accurately determination method of crude drug without extraction and separation.

Animals↗
PubMed1978

Laser Raman light-scattering observations of conformational changes in myosin induced by inorganic salts.

The Raman spectra of aqueous solutions of myosin and mixtures of myosin in solutions of the salts CaCl(2), MgCl(2), and LiBr have been taken. The spectrum of the solvent background has been subtracted by means of a computer, leaving only the Raman peaks of the protein. From an analysis of the Raman bands in the regions at 900, 940, 1,240-1,300, and 1,650-1,670 cm(-1), it seems likely that CaCl(2) effects an alpha-to beta-transition in myosin, probably owing to the interaction of the Ca(2+) ion, LiBr appears to denature the protein leading to increased random coil structure, and MgCl(2) appears to have an effect intermediate between the two other salts. These results are reported for concentrations as low as 10(-5) M of CaCl(2) and MgCl(2).This investigation indicates the usefulness of the Raman light-scattering technique for the study of protein conformational changes.

Calcium Chloride↗
PubMed2002

Raman revisited.

Explore the source record for details and available documents.

Costs and Cost Analysis↗
PubMed2004

Vibrational frequencies and structural determination of phosphorous tricyanide.

The normal mode frequencies and corresponding vibrational assignments of phosphorous tricyanide (P(CN)(3)) are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of four types of motion predicted by a group theoretical analysis P-C stretch, CN stretch, P-C[triple bond]C bend, and C-P-C bend) utilizing the C(3v) symmetry of the molecule. A uniform scaling factor was derived for each type of motion. Predicted infrared and Raman intensities are reported.

Cyanides↗
PubMed2004

Interaction of nitric oxide with cytochrome P450 BM3.

The interaction of nitric oxide with cytochrome P450 BM3 from Bacillus megaterium has been analyzed by spectroscopic techniques and enzyme assays. Nitric oxide ligates tightly to the ferric heme iron, inducing large changes in each of the main visible bands of the heme and inhibiting the fatty acid hydroxylase function of the protein. However, the ferrous adduct is unstable under aerobic conditions, and activity recovers rapidly after addition of NADPH to the flavocytochrome due to reduction of the heme via the reductase domain and displacement of the ligand. The visible spectral properties revert to that of the oxidized resting form. Aerobic reduction of the nitrosyl complex of the BM3 holoenzyme or heme domain by sodium dithionite also displaces the ligand. A single electron reduction destabilizes the ferric-nitrosyl complex such that nitric oxide is released directly, as shown by the trapping of released nitric oxide. Aerobically and in the absence of exogenous reductant, nitric oxide dissociates completely from the P450 over periods of several minutes. However, recovery of the nativelike visible spectrum is accompanied by alterations in the catalytic activity of the enzyme and changes in the resonance Raman spectrum. Specifically, resonance Raman spectroscopy identifies the presence of internally located nitrated tyrosine residue(s) following treatment with nitric oxide. Analysis of a Y51F mutant indicates that this is the major nitration target under these conditions. While wild-type P450 BM3 does not form an aerobically stable ferrous-nitrosyl complex, a site-directed mutant of P450 BM3 (F393H) does form an isolatable ferrous-nitrosyl complex, providing strong evidence for the role of this residue in controlling the electronic properties of the heme iron. We report here the spectroscopic characterization of the ferric- and ferrous-nitrosyl complexes of P450 BM3 and describe the use of resonance Raman spectroscopy to identify nitrated tyrosine residue(s) in the enzyme. Nitration of tyrosine in P450 BM3 may exemplify a typical mechanism by which the ubiquitous messenger molecule nitric oxide exerts a regulatory function over the cytochromes P450.

Bacillus megaterium↗
PubMed1985

Secondary structure of human leukocyte interferon from Raman spectroscopy.

Raman spectra were taken of human alpha (leukocyte) interferon subtype A (HuIFN-alpha A) purified from extracts of transformed Escherichia coli. Quantitative analysis of the conformationally sensitive amide I band indicates that IFN (interferon)-alpha A is 75 +/- 5% helical and 7 +/- 4% beta-strand. An independent analysis of the amide III spectrum indicates 71 +/- 5% helix and 10 +/- 6% beta-strand. These results differ with a recently proposed three-dimensional model based on secondary structure predictions derived from sequence and with circular dichroism measurements. The Raman spectrum of IFN-alpha A is compared with the spectra of several other helical proteins: hemerythrin, intestinal calcium-binding protein, melittin, and insulin.

Escherichia coli↗
PubMed1999

Laser-Raman microprobe identification of inclusions in capsules associated with silicone gel breast implants.

Raman spectroscopy (the analysis of scattered photons after excitation with a monochromatic light source) provides a nondestructive method for identifying organic and inorganic materials on the basis of the molecule's characteristic spectrum of vibrational frequencies. Although the technique has been predominantly applied in sciences other than pathology, the recent advent of high-quality microscope optics coupled to optical Raman spectrometers (a variation known as a Raman microprobe) rendered this technique amenable to applications in human pathology. In the Raman microprobe, a laser beam is focused on a spot approximately 1 microm in diameter on the surface of the sample, e.g., tissue, and the scattered light is collected and analyzed. In this investigation, we used the Raman microprobe for the identification of foreign materials in breast implant capsular tissues. The characteristic silicone group frequencies associated with the silicon-oxygen stretch, the silicone-carbon stretch, the silicon-methyl and the methyl carbon-hydrogen stretch frequencies were used to identify polydimethylsiloxane and to define chemical differences among the various other implant-related inclusions. All of the inclusions were positively identified in a series of 44 capsules from silicone gel-filled implants: polydimethylsiloxane was found in 44 of 44 capsules surrounding silicone gel-filled implants; polyurethane was seen in 4 of 4 capsules around polyurethane foam-coated gel-filled implants; 4 of 4 capsules enveloping Dacron patch gel-filled implants revealed Dacron; and talc was identified in 8 of these 44 capsules. Raman microspectroscopy provides a rapid, accurate, and sensitive method for identifying inclusions associated with silicone and other implant materials in tissue.

Breast↗
PubMed2005

Single-molecule detection of yeast cytochrome c by Surface-Enhanced Raman Spectroscopy.

The giant enhancement of Raman signal near silver colloidal nanoparticles is exploited to study the Raman spectrum of Cytochrome c from Saccharomyces cerevisiae (Yeast Cytochrome c--YCc) in the limit of single-molecule. The investigation is performed on proteins both in solution and immobilised onto a glass slide using a quasi resonant laser line as exciting source with low excitation intensity. In both cases, spectra acquired at different times exhibit dramatic temporal fluctuations in both the total spectrum and in the specific line intensity, even though averaging of several individual spectra reproduces the main Raman features of bulk YCc. Analysis of the spectral intensity fluctuations from solutions reveals a multimodal distribution of some specific Raman lines, consistent with the approaching of single molecule regime. Among other results, the statistical analysis of the spectra from immobilised samples seems to indicate dynamical processes involving the reorientational of the heme with respect to the metal surface.

Colloids↗