Biospectroscopy最新文献

{"title":"Fourier transform infrared spectroscopy as a probe for the study of the hydration of lipid self-assemblies. II. Water binding versus phase transitions","authors":"Carsten Selle,&nbsp;Walter Pohle","doi":"10.1002/(SICI)1520-6343(1998)4:4<281::AID-BSPY6>3.0.CO;2-5","DOIUrl":"10.1002/(SICI)1520-6343(1998)4:4<281::AID-BSPY6>3.0.CO;2-5","url":null,"abstract":"<p>The gradual hydration of phospholipid films can be effectively probed by Fourier transform infrared (FTIR) spectroscopy (cf. part I of this series). The hydration-induced changes observed for lipid IR-absorption bands are probably composed of contributions arising from the effects of both the direct binding of water molecules and the thereby caused conformational changes and phase transitions in the lipid molecules and assemblies, respectively. In this article, an attempt is made to attribute some of the more indicative spectroscopic results to these molecular and supermolecular processes with a view to separating their individual contributions to the relevant spectroscopic data. This is done by considering a series of suitable PLs consisting of the palmitoyl and oleoyl lecithins, DPPC, DOPC, POPC, and OPPC, and one cephalin, DOPE. This choice of PCs and DOPE means that at room temperature and different degrees of hydration, several phase states including lamellar gel and liquid crystalline as well as certain nonlamellar phases are covered. The separation of the water-binding and phase-transition contributions to the FTIR-spectroscopic data, we believe, is clearly demonstrated by interpreting the hydration-dependent wavenumber shifts of the νC=O band of the PCs. Carbonyl groups are affected to a more significant degree for lipids arrayed in the <i>L</i>_α phase than in the gel phase. A number of spectral features reveal the lyotropically triggered chain-melting transition as well as other structural rearrangements of PCs. This is discussed in detail and demonstrates the excellent sensitivity of the FTIR methodology for the study of such systems. © 1998 John Wiley &amp; Sons, Inc. Biospectroscopy 4: 281–294, 1998</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"4 4","pages":"281-294"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1998)4:4<281::AID-BSPY6>3.0.CO;2-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20622535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unfolding and aggregation-associated changes in the secondary structure of D-glyceraldehyde-3-phosphate dehydrogenase during denaturation by guanidine hydrochloride as monitored by FTIR","authors":"Xiao-Feng Li,&nbsp;Jun-Mei Zhou","doi":"10.1002/(SICI)1520-6343(1997)3:2<121::AID-BSPY5>3.0.CO;2-A","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:2<121::AID-BSPY5>3.0.CO;2-A","url":null,"abstract":"<p>The secondary structure of native <span>D</span>-glyceraldehyde-3-phosphate dehydrogenase was compared with its partially folded intermediate and aggregated states obtained during guanidine hydrochloride (GdnHCl) denaturation using transmission Fourier transform infrared (FTIR) and micro-FTIR measurements. The changes in the secondary structures indicated a partially folded intermediate formed in 0.1<i>M</i> GdnHCl solution without visible aggregation. Increasing the GdnHCl concentration resulted in aggregation of the enzyme along with changes in the secondary structure. Although similar relative amounts of the secondary structure were found in the aggregated and native states of the enzyme, the temporal variation of the secondary structure revealed a difference in the β-sheet structure between the aggregated and native states, suggesting that the aggregation resulted from further unfolding of the enzyme. In addition, FTIR data suggest that such aggregates are most likely mediated by specific intermolecular interactions and that the predominant driving force involved in aggregation may be a hydrophobic interaction between exposed surfaces of partially folded intermediates. © 1997 John Wiley &amp; Sons, Inc. Biospect <b>3:</b> 121–129, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 2","pages":"121-129"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:2<121::AID-BSPY5>3.0.CO;2-A","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83722497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR analysis of the ultraviolet photolytic behavior of several tryptophan-rich growth hormone releasing peptides","authors":"Steve McKim,&nbsp;James F. Hinton,&nbsp;Romano Deghenghi","doi":"10.1002/(SICI)1520-6343(1997)3:4<317::AID-BSPY7>3.0.CO;2-0","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:4<317::AID-BSPY7>3.0.CO;2-0","url":null,"abstract":"<p>Aqueous solutions of three tryptophan-rich growth hormone releasing hexapeptides, GHRP-6 (His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂), hexarelin (His-D-2-Me-Trp-Ala-Trp-D-Phe-Lys-NH₂), and EP7458 (His-D-Trp-Ala-2-Me-Trp-D-Phe-Lys-NH₂), were exposed to varying durations of ultraviolet (UV) light. Using NMR spectroscopy, first-order rate constants for the UV photolytic degradation of the tryptophan(s)/2-methyl tryptophan residues within each peptide were obtained by plotting the decrease in the area of the indole N-H resonances with respect to UV photolysis time. A significant differential photolytic effect was observed between the two tryptophan residues of GHRP-6 and the tryptophan/2-methyl tryptophan residues of EP7458. A somewhat smaller differential photolytic effect was observed between the tryptophan/2-methyl tryptophan residues of hexarelin. In addition, the three peptides were degraded at different rates, suggesting that the effect of UV light on each peptide is dependent on whether a tryptophan or 2-methyl tryptophan is the second or fourth residue in the primary sequence. © 1997 John Wiley &amp; Sons, Inc. Biospectroscopy <b>3:</b> 317–323, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 4","pages":"317-323"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:4<317::AID-BSPY7>3.0.CO;2-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85260328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of the stability of complexes between DNA and the thiazole orange derivatives TO6 and TOTO by surface-enhanced resonance Raman spectroscopy","authors":"M. Nissum,&nbsp;J. P. Jacobsen,&nbsp;O. Faurskov Nielsen,&nbsp;P. Waage Jensen","doi":"10.1002/(SICI)1520-6343(1997)3:3<207::AID-BSPY4>3.0.CO;2-2","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:3<207::AID-BSPY4>3.0.CO;2-2","url":null,"abstract":"<p>Complexes of the two thiazole orange derivatives TO6 [1-(N,N′-tetramethyl-1,3-propanediaminopropyl)-4-[3-methyl-2,3-dihydro(benzo-1,3-thiazole)-2-methylidene] quinolinium triiodide] and TOTO [1,1'-(4,4,8,8-tetramethyl-4,8-diazaundecamethylene)bis-4-[3-methyl-2,3-dihydro(benzo-1,3-thiazole)-2-methylidene] quinolinium tetraiodide] with DNA oligonucleotide strands are investigated by the use of surface-enhanced resonance Raman spectroscopy. TO6 and TOTO contain protons that are exchangeable with deuterium when dissolved in D₂O. The exchange sites can be identified by use of nuclear magnetic resonance spectroscopy. The degree of exchange observed in the surface-enhanced resonance Raman spectra is used to measure the stability of the complexes formed. TOTO forms a highly stable complex with the d(5′-CCGCTAGCG-3′): d(5′-CGCTAGCGG-3′) oligonucleotide, whereas a less stable complex is formed with d(5′-CGCGTTAACGCG-3′)₂, indicating some degree of site specificity in the binding of TOTO to DNA. TO6 does not bind strongly to any single site in the d(5′-CGCGTTAACGCG-3′)₂ oligonucleotide. © 1997 John Wiley &amp; Sons, Inc. Biospect 3: 207–213, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 3","pages":"207-213"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:3<207::AID-BSPY4>3.0.CO;2-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84161606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyses by Fourier transform infrared spectroscopies of protein structures of soluble NADH-cytochrome b5 reductases prepared by site-directed mutagenesis: Comparison with ferredoxin-NADP+ reductase","authors":"Satoshi Yoshida,&nbsp;Toshitsugu Yubisui,&nbsp;Komei Shirabe,&nbsp;Masazumi Takeshita","doi":"10.1002/(SICI)1520-6343(1997)3:3<215::AID-BSPY5>3.0.CO;2-4","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:3<215::AID-BSPY5>3.0.CO;2-4","url":null,"abstract":"<p>Fourier-transform infrared (FTIR) spectroscopy was used to study the change of protein structure of NADH-cytochrome b₅ reductase in a soluble form. Recombinant mutant cytochrome b₅ reductases, serine 127 to proline (S127P), and alanine (S127A) were investigated, where the mutation on Ser-127 to proline is a case found in patients of type II methemoglobinemia. The secondary structure of cytochrome b₅ reductase was revealed tentatively by FTIR using resolution enhancement and band-fitting techniques, providing the contents of α-helix (22%), β-sheet (30%), random coil (27%), and β-turn (22%) for the wild-type cytochrome b₅ reductase. The mutant enzyme, S127P, was more sensitive to the thermal denaturation than the wild type with increasing β-sheet structures observed at 1624 and 1672 cm⁻¹ during the heat treatment and relatively decreasing in intensities of bands around 1640–1660 cm⁻¹ during heat treatment. The secondary structure of ferredoxin-NADP⁺ reductase, one of the same family as cytochrome b₅ reductase, predicted from FTIR data was similar to that of the wild-type cytochrome b₅ reductase but significantly different in the content of β-sheet and was consistent with the X-ray crystallographic data of ferredoxin-NADP⁺ reductase. The mutation on Ser-127 to proline or alanine in cytochrome b₅ reductase caused only a small change (3 or 9%, respectively) in total of α-helix, random coil, and β-turn contents and almost no change in the β-sheet content. These results suggest that the lability of the mutated cytochrome b₅ reductases might not result simply from the secondary structural change but from possibly the tertiary structural change, including the peptide side chain positional and the protein-protein interactional changes. © 1997 John Wiley &amp; Sons, Inc. Biospect 3: 215–223, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 3","pages":"215-223"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:3<215::AID-BSPY5>3.0.CO;2-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77519170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Removal of spectral noise in the quantitation of protein structure through infrared band decomposition","authors":"Izaskun Echabe,&nbsp;José Antonio Encinar,&nbsp;José Luis R. Arrondo","doi":"10.1002/(SICI)1520-6343(1997)3:6<469::AID-BSPY6>3.0.CO;2-W","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:6<469::AID-BSPY6>3.0.CO;2-W","url":null,"abstract":"<p>The underlying noise in the infrared spectra of proteins may introduce artifacts in the quantitation of proteins by curve-fitting of the amide I band. Smoothing methods are able to reduce the noise but can introduce alterations in band shape that affect the information contained in the spectrum. Three methods to remove noise—Savitzky-Golay, Fourier filtering, and maximum entropy—have been used to ascertain their influence on the quantitative information when applied to protein bands. Use of artificial curves shows that whereas Savitzky-Golay and Fourier smoothing are able to reduce the noise, they distort the band shape. Maximum entropy is more efficient in reducing the noise in artificial curves with added noise, and provided a narrowest bandwidth below 12 cm⁻¹, no band-shape distortion is obtained. Using the smoothing in natural spectra, the presence of spurious bands in the initial parameters coming from artifacts introduced by deconvolution or derivation is reduced. Moreover, the dispersion in the percentage area values in a series of similar spectra is also decreased below 2%, a value that discriminates the effect of ligand binding to proteins. The maximum entropy method is proposed as a tool to improve the quantification of protein structure by infrared spectroscopy. © 1997 John Wiley &amp; Sons, Inc. Biospectroscopy <b>3:</b> 469–475, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 6","pages":"469-475"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:6<469::AID-BSPY6>3.0.CO;2-W","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82574014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The interactions between cellular retinol-binding protein (CRBP-I) and retinal: A vibrational spectroscopic study","authors":"Larry Senak,&nbsp;Zhongmo Ju,&nbsp;Noa Noy,&nbsp;Robert Callender,&nbsp;Danny Manor","doi":"10.1002/(SICI)1520-6343(1997)3:2<131::AID-BSPY6>3.0.CO;2-A","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:2<131::AID-BSPY6>3.0.CO;2-A","url":null,"abstract":"<p>Preresonance Raman difference spectra have been obtained for all-<i>trans</i> retinal in dilute CCl₄ solution, complexed with cellular retinol-binding protein (CRBP-I) and retinol-binding protein (RBP). These spectra indicate that retinal is of a slightly more planar conformation within the binding pocket of CRBP-I than in solution or hydrophobically complexed with RBP. Compared to retinal in solution or bound to RBP, the conformation of the polyene tail of the retinal chromophore is perturbed from C8 through C11. This perturbation is probably due to the close proximity of the Lys40 in the CRBP-I binding pocket to the above-mentioned carbons. The C(DOUBLE BOND)O stretching vibration of bound retinal carbonyl has been found to shift from 1664 cm⁻¹ solubilized in CCl₄ to 1650 and 1645 cm⁻¹ in RBP and CRBP-I, respectively, and significantly broadened in both cases. The frequency shift and broadening have been attributed to hydrogen bonding. These have been compared to calibrations of frequency shift (Δν_{C(DOUBLE BOND)O}) vs. Δ<i>H</i> and Δ<i>G</i> of all-<i>trans</i> retinal complexed with a series of phenol derivatives of incremental proton-donating ability as obtained by the relationship of van't Hoff. By this relationship, the binding enthalpy of the all-<i>trans</i> retinal carbonyl moiety bound to CRBP-I and RBP is −28.1 kJ/mol (−6.7 kcal/mol) and −23.5 kJ/mol (−5.6 kcal/mol), respectively. The free energy of binding of the retinal carbonyl bound to CRBP-I and RBP has been determined to be −10.5 kJ/mol (−2.5 kcal/mol) and −7.2 kJ/mol (−1.7 kcal/mol), respectively. The hydrogen-bonded C(DOUBLE BOND)O moiety of retinal complexed with CRBP-I accounts for a substantial (25%) but not overriding amount of the binding energy of CRBP-I for retinal, and it also accounts for the protein's preference for binding retinol. © 1997 John Wiley &amp; Sons, Inc. Biospect <b>3:</b> 131–142, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 2","pages":"131-142"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:2<131::AID-BSPY6>3.0.CO;2-A","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80785377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fourier transform infrared spectroscopic analysis of rat brain microsomal membranes modified by dietary fatty acids: Possible correlation with altered learning behavior","authors":"S. Yoshida,&nbsp;M. Miyazaki,&nbsp;K. Sakai,&nbsp;M. Takeshita,&nbsp;S. Yuasa,&nbsp;A. Sato,&nbsp;T. Kobayashi,&nbsp;S. Watanabe,&nbsp;H. Okuyama","doi":"10.1002/(SICI)1520-6343(1997)3:4<281::AID-BSPY3>3.0.CO;2-7","DOIUrl":"10.1002/(SICI)1520-6343(1997)3:4<281::AID-BSPY3>3.0.CO;2-7","url":null,"abstract":"<p>We measured the Fourier transform infrared spectra of brain microsomal membranes prepared from rats fed under two dietary oil conditions with and without brightness-discrimination learning tasks: one group fed α-linolenate deficient oil (safflower oil) and the other group fed the sufficient oil (perilla oil) from mothers to offspring. The infrared spectra of microsomes under the two dietary conditions without the learning task showed no significant difference in the range 1000–3000 cm⁻¹. Only after the learning task were the infrared spectral differences noted between the microsomal membranes from both groups. Spectral differences were observed mainly in the absorption bands of fatty acid ester at around 1730 cm⁻¹ (sn-2 position), those of phosphate and oligosaccharides in the range of 1050–1100 cm⁻¹, and a band at around 1145 cm⁻¹. The infrared band of fatty acid ester at the sn-2 position in the microsomal membrane shifted to a longer wavenumber position in the perilla oil group than in the safflower oil group, suggesting a difference between both groups in hydrogen bonding of the fatty acid ester with water. A band observed at 1055 cm⁻¹ and a small band at around 1145 cm⁻¹ in the second derivative spectrum decreased in intensity in the perilla oil group after learning task. These bands were assigned mainly to the oligosaccharide C—O bond in hydroxyl groups that might interact with some other membrane components. These results suggest changes in hydration of membrane surface and modification in oligosaccharide environment (removal or modification) of microsomes, which may be correlated in part with dietary oil-induced changes in learning performance. © 1997 John Wiley &amp; Sons, Inc. Biospectroscopy <b>3:</b> 281–290, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 4","pages":"281-290"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1997)3:4<281::AID-BSPY3>3.0.CO;2-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80129029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An introduction to electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry: Essential tools in a modern biotechnology environment","authors":"Cornelis E. C. A. Hop,&nbsp;Ray Bakhtiar","doi":"10.1002/(SICI)1520-6343(1997)3:4<259::AID-BSPY2>3.0.CO;2-%23","DOIUrl":"https://doi.org/10.1002/(SICI)1520-6343(1997)3:4<259::AID-BSPY2>3.0.CO;2-%23","url":null,"abstract":"<p>The tremendous progress in biochemistry and biotechnology has been made possible in part by recent advances in analytical methods, in particular mass spectrometry. With the introduction of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI), mass spectrometry allowed the determination of the molecular weight of peptides and proteins with a much greater accuracy than achievable by traditional methods such as SDS-PAGE and biogel chromatography. In addition, these mass spectrometry experiments have become routine and can be performed within minutes. ESI and MALDI (in combination with enzymatic methods) can also provide vital structural data such as the amino acid sequence and the sites of posttranslational modifications for peptides and proteins with a sensitivity that competes favorably with other methods. The use of ESI and MALDI is not limited to peptides and proteins; analysis of oligonucleotides and oligosaccharides has been simplified by these techniques as well. For information about structurally significant noncovalent interaction between various types of biomolecules, ESI is probably one of the most convenient methods. Not surprisingly, we anticipate that the mass spectrometers with these ionization capabilities will soon become standard equipment in all pharmaceutical and biotechnology laboratories. © 1997 John Wiley &amp; Sons, Inc. Biospectroscopy <b>3:</b> 259–280, 1997</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"3 4","pages":"259-280"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137648547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for global mobility in the premelting of a polynucleotide from temperature-dependent Raman optical activity","authors":"Alasdair F. Bell,&nbsp;Lutz Hecht,&nbsp;Laurence D. Barron","doi":"10.1002/(SICI)1520-6343(1998)4:2<107::AID-BSPY3>3.0.CO;2-2","DOIUrl":"10.1002/(SICI)1520-6343(1998)4:2<107::AID-BSPY3>3.0.CO;2-2","url":null,"abstract":"<p>The backscattered Raman and Raman optical activity (ROA) spectra of poly(rA)-poly(rU) at 20°C and 45°C in buffered aqueous solution between 650 and 1750 cm⁻¹ are reported. Although the intensity of the majority of the Raman bands increase by varying amounts as the temperature is raised in accordance with the well-known hypochromic effect, the reverse effect is found for the ROA signals which we attribute to thermal accessibility of a greater number of distinct conformations leading to cancellation of ROA signals. The difference ROA spectrum obtained by subtracting the spectrum recorded at 45°C from that recorded at 20°C displays a very similar sign pattern to those at both 20°C and 45°C throughout the spectral region examined. This indicates that the same average structure is maintained in this temperature range and that the thermal fluctuations are correlated through the bases, the glycosidic link, the sugar ring, and the phosphate backbone of both strands. These results indicate that ROA may be a useful new probe of the dynamics of nucleic acid in solution. © 1998 John Wiley &amp; Sons, Inc. Biospectroscopy 4: 107–111, 1998</p>","PeriodicalId":9037,"journal":{"name":"Biospectroscopy","volume":"4 2","pages":"107-111"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/(SICI)1520-6343(1998)4:2<107::AID-BSPY3>3.0.CO;2-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20480267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}