Infrared spectroscopy of proteins and peptides in lipid bilayers

Tamm, Lukas K.; Tatulian, Suren A.

doi:10.1017/s0033583597003375

Cited by 672 publications

(750 citation statements)

References 218 publications

Supporting

Mentioning

704

Contrasting

Unclassified

Order By: Relevance

“…The spectral differences between the Gleason scores (Table 2 and Figure 3) occur in the amide I (1600 -1700 cm À1 ), amide II (1510 -1580 cm À1 ) and amide III (1200 - Spectral assignments taken from references Meurens et al (1996); Tamm and Tatulain (1997); Dovbeshko et al (2000); Naumann (2001);Cai and Ram Singh (2004);and Meade et al (2007).…”

Section: Discussion Correlation Of Ftir Pc-dfa Spectral Signature Witmentioning

confidence: 99%

FTIR-based spectroscopic analysis in the identification of clinically aggressive prostate cancer

et al. 2008

View full text Add to dashboard Cite

Fourier transform infrared (FTIR) spectroscopy is a vibrational spectroscopic technique that uses infrared radiation to vibrate molecular bonds within the sample that absorbs it. As different samples contain different molecular bonds or different configurations of molecular bonds, FTIR allows us to obtain chemical information on molecules within the sample. Fourier transform infrared microspectroscopy in conjunction with a principal component-discriminant function analysis (PC-DFA) algorithm was applied to the grading of prostate cancer (CaP) tissue specimens. The PC-DFA algorithm is used alongside the established diagnostic measures of Gleason grading and the tumour/node/metastasis system. Principal component-discriminant function analysis improved the sensitivity and specificity of a three-band Gleason score criterion diagnosis previously reported by attaining an overall sensitivity of 92.3% and specificity of 99.4%. For the first time, we present the use of a two-band criterion showing an association of FTIR-based spectral characteristics with clinically aggressive behaviour in CaP manifest as local and/or distal spread. This paper shows the potential for the use of spectroscopic analysis for the evaluation of the biopotential of CaP in an accurate and reproducible manner.

show abstract

Section: Discussion Correlation Of Ftir Pc-dfa Spectral Signature Witmentioning

confidence: 99%

FTIR-based spectroscopic analysis in the identification of clinically aggressive prostate cancer

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The orientation of a structural element was calculated from the dichroic ratio, R ϭ A 0°/ A 90°, where A 0°a nd A 90°a re the absorption bands of the functional group of that element in the parallel and perpendicular configuration, respectively (38,39). The form factor, S, was derived from R using Equation 2 (40),…”

Section: Methodsmentioning

confidence: 99%

Pore Formation by Equinatoxin II, a Eukaryotic Protein Toxin, Occurs by Induction of Nonlamellar Lipid Structures

Anderluh

Serra

Viero

et al. 2003

Journal of Biological Chemistry

125

109

View full text Add to dashboard Cite

Pore formation in the target cell membranes is a common mechanism used by many toxins in order to kill cells. Among various described mechanisms, a toroidal pore concept was described recently in the course of action of small antimicrobial peptides. Here we provide evidence that such mechanism may be used also by larger toxins. Membrane-destabilizing effects of equinatoxin II, a sea anemone cytolysin, were studied by various biophysical techniques. 31 P NMR showed an occurrence of an isotropic component when toxin was added to multilamellar vesicles and heated. This component was not observed with melittin, ␣-staphylococcal toxin, or myoglobin. It does not originate from isolated small lipid structures, since the size of the vesicles after the experiment was similar to the control without toxin. Electron microscopy shows occurrence of a honeycomb structure, previously observed only for some particular lipid mixtures. The analysis of FTIR spectra of the equinatoxin II-lipid complex showed lipid disordering that is consistent with isotropic component observed in NMR. Finally, the cation selectivity of the toxin-induced pores increased in the presence of negatively charged phosphatidic acid, indicating the presence of lipids in the conductive channel. The results are compatible with the toroidal pore concept that might be a general mechanism of pore formation for various membrane-interacting proteins or peptides.Proteins and peptides with the capacity to increase membrane permeability have been elaborated by a large number of organisms and are used as toxins, effectors in immune response or apoptosis. One of the most commonly adopted mechanisms is the formation of pores in the targeted membrane as occurs, for example, with pore-forming toxins (PFT) 1 (1, 2).Bacterial PFT, protein molecules of M r Ͼ 30,000, usually follow two strategies; they either form a channel via insertion of a de novo generated transmembrane ␤ barrel (examples are staphylococcal ␣-toxin, the cholesterol-dependent cytolysins, and the protective antigen of anthrax toxin), or they insert a bundle of preexisting ␣-helices through the membrane (like colicins and crystal ␦-endotoxins) (3, 4). Smaller molecules, like antimicrobial peptides or peptide toxins with M r between 1000 and 5000, have developed a wider set of mechanisms (5). In fact, besides the ␤-barrel (e.g. protegrin) (6) and the ␣-helix bundle (e.g. alamethicin and other peptaibols) (7), some alternative strategies were found, which directly modify the bilayer organization of the membrane. They range from a generic destabilization (exemplified by the carpet-like model) (8) to the formation of specific mixed lipid-peptide structures, like the toroidal pore, which was observed with magainin (9) and melittin (10).Actinoporins are a peculiar class of eukaryotic PFT with intermediate M r , exclusively found in sea anemones. It is a family of cysteineless proteins with M r around 18,000 -20,000 and a preference for sphingomyelin (SM) (11). They form cation-selective pores with a diameter of ϳ2...

show abstract

“…On the other hand, the L-LHCII samples are characterized by higher intensities in the spectral band with the maximum at 1688 cm 21 . This spectral region can be formally attributed to antiparallel b-sheet structures (Tamm and Tatulian, 1997), and it represents, most probably, the b-like structures stabilized by the hydrogen bonds between the polar loops of the LHCII complexes involved in the formation of the trans-layer, integrated supramolecular structures. The samples formed with LHCII are referred to as L-LHCII and formed with LHCII-HL are referred to as L-LHCII-HL.…”

Section: Infrared Analysis Of the Lipid-protein Multibilayersmentioning

confidence: 98%

Molecular Architecture of Plant Thylakoids under Physiological and Light Stress Conditions: A Study of Lipid-Light-Harvesting Complex II Model Membranes

et al. 2013

View full text Add to dashboard Cite

In this study, we analyzed multibilayer lipid-protein membranes composed of the photosynthetic light-harvesting complex II (LHCII; isolated from spinach [Spinacia oleracea]) and the plant lipids monogalcatosyldiacylglycerol and digalactosyldiacylglycerol. Two types of pigment-protein complexes were analyzed: those isolated from dark-adapted leaves (LHCII) and those from leaves preilluminated with high-intensity light (LHCII-HL). The LHCII-HL complexes were found to be partially phosphorylated and contained zeaxanthin. The results of the x-ray diffraction, infrared imaging microscopy, confocal laser scanning microscopy, and transmission electron microscopy revealed that lipid-LHCII membranes assemble into planar multibilayers, in contrast with the lipid-LHCII-HL membranes, which form less ordered structures. In both systems, the protein formed supramolecular structures. In the case of LHCII-HL, these structures spanned the multibilayer membranes and were perpendicular to the membrane plane, whereas in LHCII, the structures were lamellar and within the plane of the membranes. Lamellar aggregates of LHCII-HL have been shown, by fluorescence lifetime imaging microscopy, to be particularly active in excitation energy quenching. Both types of structures were stabilized by intermolecular hydrogen bonds. We conclude that the formation of trans-layer, rivet-like structures of LHCII is an important determinant underlying the spontaneous formation and stabilization of the thylakoid grana structures, since the lamellar aggregates are well suited to dissipate excess energy upon overexcitation.

show abstract

Infrared spectroscopy of proteins and peptides in lipid bilayers

Cited by 672 publications

References 218 publications

FTIR-based spectroscopic analysis in the identification of clinically aggressive prostate cancer

FTIR-based spectroscopic analysis in the identification of clinically aggressive prostate cancer

Pore Formation by Equinatoxin II, a Eukaryotic Protein Toxin, Occurs by Induction of Nonlamellar Lipid Structures

Molecular Architecture of Plant Thylakoids under Physiological and Light Stress Conditions: A Study of Lipid-Light-Harvesting Complex II Model Membranes

Contact Info

Product

Resources

About