scholarly journals On the Protein Fibrillation Pathway: Oligomer Intermediates Detection Using ATR-FTIR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 970
Author(s):  
Jelica Milošević ◽  
Radivoje Prodanović ◽  
Natalija Polović
Keyword(s):  
Secondary Structure ◽  
Ftir Spectroscopy ◽  
Internal Standard ◽  
Thioflavin T ◽  
Lag Phase ◽  
Standard Methods ◽  
Qualitative And Quantitative ◽  
Structure Changes ◽  
Tht Fluorescence ◽  
Amyloid Fibrillation

Oligomeric intermediates on the pathway of amyloid fibrillation are suspected as the main cytotoxins responsible for amyloid-related pathogenicity. As they appear to be a part of the lag phase of amyloid fibrillation when analyzed using standard methods such as Thioflavin T (ThT) fluorescence, a more sensitive method is needed for their detection. Here we apply Fourier transform infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode for fast and cheap analysis of destabilized hen-egg-white lysozyme solution and detection of oligomer intermediates of amyloid fibrillation. Standard methods of protein aggregation analysis— Thioflavin T (ThT) fluorescence, atomic force microscopy (AFM), and 8-anilinonaphthalene-1-sulphonic acid (ANS) fluorescence were applied and compared to FTIR spectroscopy data. Results show the great potential of FTIR for both, qualitative and quantitative monitoring of oligomer formation based on the secondary structure changes. While oligomer intermediates do not induce significant changes in ThT fluorescence, their secondary structure changes were very prominent. Normalization of specific Amide I region peak intensities by using Amide II peak intensity as an internal standard provides an opportunity to use FTIR spectroscopy for both qualitative and quantitative analysis of biological samples and detection of potentially toxic oligomers, as well as for screening of efficiency of fibrillation procedures.

scholarly journals Systematic FTIR Spectroscopy Study of the Secondary Structure Changes in Human Serum Albumin under Various Denaturation Conditions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 359 ◽  
Author(s):  
Usoltsev ◽  
Sitnikova ◽  
Kajava ◽  
Uspenskaya
Keyword(s):  
Secondary Structure ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Ftir Spectroscopy ◽  
Conformational Changes ◽  
Data Interpretation ◽  
Random Coil ◽  
Helical Conformation ◽  
Structure Changes

Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data about its conformational changes upon different denaturation factors are fragmentary and sometimes contradictory. This is especially true for FTIR spectroscopy data interpretation. Here, the effect of various denaturing agents on the structural state of HSA by using FTIR spectroscopy in the aqueous solutions was systematically studied. Our data suggest that the second derivative deconvolution method provides the most consistent interpretation of the obtained IR spectra. The secondary structure changes of HSA were studied depending on the concentration of the denaturing agent during acid, alkaline, and thermal denaturation. In general, the denaturation of HSA in different conditions is accompanied by a decrease in α-helical conformation and an increase in random coil conformation and the intermolecular β-strands. Meantime, some variation in the conformational changes depending on the type of the denaturation agent were also observed. The increase of β-structural conformation suggests that HSA may form amyloid-like aggregates upon the denaturation.

scholarly journals Candida albicans Als Adhesins Have Conserved Amyloid-Forming Sequences

2007 ◽  
Vol 7 (5) ◽  
pp. 776-782 ◽  
Author(s):  
Henry N. Otoo ◽  
Kyeng Gea Lee ◽  
Weigang Qiu ◽  
Peter N. Lipke
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Secondary Structure ◽  
Congo Red ◽  
Host Tissue ◽  
Thioflavin T ◽  
Amyloid Fibers ◽  
Conserved Sequence ◽  
Structure Changes ◽  
Cellular Aggregation

ABSTRACT The cell wall-bound Als adhesins of Candida albicans mediate both yeast-to-host tissue adherence and yeast aggregation. This aggregation is amyloid-like, with self-propagating secondary-structure changes, amyloid-characteristic dye binding, and induced birefringence (J. M. Rauceo, N. K. Gaur, K. G. Lee, J. E. Edwards, S. A. Klotz, and P. N. Lipke, Infect. Immun. 72:4948-4955, 2004). Therefore, we determined whether Als proteins could form amyloid fibers with properties like those in cellular aggregation. The β-aggregation predictor TANGO identified a heptapeptide sequence present in a highly conserved sequence with amyloid-forming potential in Als1p, Als3p, and Als5p. A tridecapeptide containing this sequence formed fibers that bound Congo red and thioflavin T and had characteristic amyloid morphology. Als5p20-431 and Als5p20-664, large fragments of Als5p containing the amyloid sequence, also formed amyloid-like fibers and bound Congo red under native conditions. Ka /Ks analysis showed that the amyloid-forming sequences are highly conserved in Als proteins and evolve more slowly than other regions of the proteins. Therefore, amyloid-forming ability itself is conserved in these proteins.

Using synchrotron FTIR spectroscopy to determine secondary structure changes and distribution in thermoplastic protein

2013 ◽  
Vol 130 (1) ◽  
pp. 359-369 ◽  
Author(s):  
James Michael Bier ◽  
Casparus Johannes Reinhard Verbeek ◽  
Mark Christopher Lay
Keyword(s):  
Secondary Structure ◽  
Ftir Spectroscopy ◽  
Structure Changes ◽  
Thermoplastic Protein

Qualitative and Quantitative Determination of Methaqualone in Serum by Gas Chromatography

1974 ◽  
Vol 20 (2) ◽  
pp. 249-254 ◽  
Author(s):  
M A Evenson ◽  
G L Lensmeyer
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Serum Concentrations ◽  
Single Extraction ◽  
Qualitative And Quantitative ◽  
Gas Chromatographic Method ◽  
Isothermal Gas

Abstract A rapid, simple, accurate, and precise isothermal gas-chromatographic method is introduced for determination of methaqualone (2-methyl-3-o-tolyl-4(3H)-quinazolinone) in serum. A single extraction of 2 ml of serum, without derivative formation, will give adequate sensitivity for quantitation of therapeutic serum concentrations of the drug within 15 min. The method is free of interferences from biological substances, as well as from commonly used drugs. A non-drug internal standard compensates for variables in extraction, injection, and instrumental changes during analysis. The coefficient of variation, day-to-day, is 5.6%. Mean recovery of added methaqualone was 80%. To compensate for the nonquantitative yield and ensure accurate results, we prepared all analytical methaqualone standards in serum.

METHOD OF QUANTITATIVE ANALYSIS MAKING USE OF BROMINE IN A NUCLEPORE FILTER

1997 ◽  
Vol 07 (01n02) ◽  
pp. 71-85 ◽  
Author(s):  
K. SERA ◽  
S. FUTATSUGAWA ◽  
K. SAITOH
Keyword(s):  
Quantitative Analysis ◽  
Atmospheric Aerosols ◽  
Present Method ◽  
Total Yield ◽  
Internal Standard ◽  
X Rays ◽  
Light Elements ◽  
Standard Methods ◽  
Nuclepore Filter

Nuclepore filters have been widely used for collecting atmospheric aerosols and such samples are quite convenient for PIXE since they can be analyzed without any treatment. However, some special methods, (which is somewhat different from existing standard methods for general samples), must be applied in order to perform quantitative analysis. We have developed a method of quantitative analysis for all elements making use of bromine, which is almost uniformly contained in general Nuclepore filters, as an internal standard. Then, for quantitative analysis of light elements, the standard-free method, which makes use of total yield of continuous x-rays, has been applied and it is found that this method can be successfully applied to practical aerosol samples. Moreover, the method was applied to bio-samples prepared by cutting frozen samples with a microtome, and the result is almost satisfactory. It is found that the present method can be successfully applied to any sample which can be made uniform.

The Secondary Structure of the Inhibited Mitochondrial ADP/ATP Transporter from Yeast Analyzed by FTIR Spectroscopy†

Biochemistry ◽  
2001 ◽  
Vol 40 (30) ◽  
pp. 8821-8833 ◽  
Author(s):  
Víctor A. Lórenz ◽  
Joaquim Villaverde ◽  
Véronique Trézéguet ◽  
Guy J.-M. Lauquin ◽  
Gérard Brandolin ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Ftir Spectroscopy
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