Temat: fluorescence quenching - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: In vitro fluorescence studies of transcription factor IIB-DNA interaction
Autorzy:: Górecki, Andrzej
Figiel, Małgorzata
Dziedzicka-Wasylewska, Marta
Powiązania:: https://bibliotekanauki.pl/articles/1038975.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: transcription factors
TF2B
TFIIB
fluorescence spectroscopy
fluorescence quenching
site directed mutagenesis
Opis:: General transcription factor TFIIB is one of the basal constituents of the preinitiation complex of eukaryotic RNA polymerase II, acting as a bridge between the preinitiation complex and the polymerase, and binding promoter DNA in an asymmetric manner, thereby defining the direction of the transcription. Methods of fluorescence spectroscopy together with circular dichroism spectroscopy were used to observe conformational changes in the structure of recombinant human TFIIB after binding to specific DNA sequence. To facilitate the exploration of the structural changes, several site-directed mutations have been introduced altering the fluorescence properties of the protein. Our observations showed that binding of specific DNA sequences changed the protein structure and dynamics, and TFIIB may exist in two conformational states, which can be described by a different microenvironment of W52. Fluorescence studies using both intrinsic and exogenous fluorophores showed that these changes significantly depended on the recognition sequence and concerned various regions of the protein, including those interacting with other transcription factors and RNA polymerase II. DNA binding can cause rearrangements in regions of proteins interacting with the polymerase in a manner dependent on the recognized sequences, and therefore, influence the gene expression.
Źródło:: Acta Biochimica Polonica; 2015, 62, 3; 413-421
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 2.

Tytuł:: Interaction of three Caenorhabditis elegans isoforms of translation initiation factor eIF4E with mono- and trimethylated mRNA 5 cap analogues.
Autorzy:: Stachelska, Alicja
Wieczorek, Zbigniew
Ruszczyńska, Katarzyna
Stolarski, Ryszard
Pietrzak, Monika
Lamphear, Barry
Rhoads, Robert
Darżynkiewicz, Edward
Jankowska-Anyszka, Marzena
Powiązania:: https://bibliotekanauki.pl/articles/1043732.pdf
Data publikacji:: 2002
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: fluorescence quenching
eIF4E
Caenorhabditis elegans
mRNA 5' cap
translation initiation
Opis:: Translation initiation factor eIF4E binds the m7G cap of eukaryotic mRNAs and mediates recruitment of mRNA to the ribosome during cap-dependent translation initiation. This event is the rate-limiting step of translation and a major target for translational control. In the nematode Caenorhabditis elegans, about 70% of genes express mRNAs with an unusual cap structure containing m32,2,7G, which is poorly recognized by mammalian eIF4E. C. elegans expresses five isoforms of eIF4E (IFE-1, IFE-2, etc.). Three of these (IFE-3, IFE-4 and IFE-5) were investigated by means of spectroscopy and structural modelling based on mouse eIF4E bound to m7GDP. Intrinsic fluorescence quenching of Trp residues in the IFEs by iodide ions indicated structural differences between the apo and m7G cap bound proteins. Fluorescence quenching by selected cap analogues showed that only IFE-5 forms specific complexes with both m7G- and m32,2,7G-containing caps (Kas 2×106 M-1 to 7×106 M-1) whereas IFE-3 and IFE-4 discriminated strongly in favor of m7G-containing caps. These spectroscopic results quantitatively confirm earlier qualitative data derived from affinity chromatography. The dependence of Kas on pH indicated optimal cap binding of IFE-3, IFE-4 and IFE-5 at pH 7.2, lower by 0.4 pH units than that of eIF4E from human erythrocytes. These results provide insight into the molecular mechanism of recognition of structurally different caps by the highly homologous IFEs.
Źródło:: Acta Biochimica Polonica; 2002, 49, 3; 671-682
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 3.

Tytuł:: SCREENING THE SPECIFIC SUBSTRATES OF ADENYLATION DOMAIN FROM MARINE ACTINOMYCETES BY FLUORESCENCE QUENCHING AND ISOTHERMAL TITRATION CALORIMETRY
Autorzy:: LEI, MING
ZHAO, ZHIJUAN
LIU, KE
LIU, YANLI
ZHANG, HUI
WU, XUE
GONG, SIYING
MA, YANLING
ZHAO, HAOBIN
LIU, JINLIN
MIN, JINRONG
QI, CHAO
Powiązania:: https://bibliotekanauki.pl/articles/895432.pdf
Data publikacji:: 2018-12-31
Wydawca:: Polskie Towarzystwo Farmaceutyczne
Tematy:: A domain
Aspartic acid
Fluorescence quenching (FQ)
Isothermal titration calorimetry (ITC)
Marine actinomycetes
static quenching
Opis:: Adenylation domain (A domain) is a model of non-ribosomal peptide synthetases (NRPs), responsible for binding and activating the substrates-amino acids. In this study, a pGEX-2T-sare0718 recombinant plasmid (the gene sare0718 was cloned from Salinispora arenicola CNS-205, S.arenicola CNS-205) was transformed and expressed as a protein GST-Sare0718. Fluorescence quenching (FQ) was conducted to investigate the binding of 20 common amino acids to GST-Sare0718, then isothermal titration calorimetry (ITC) also be used[changed]. The results of FQ revealed that intrinsic fluorescence of GST-Sare0718 is quenched steadily by addition of aspartic acid (Asp) and glutamine (Gln) through static quenching mechanism. The binding constants Ka are Asp (1.504×106 L/mol) ≥ Gln (1.468×105 L/mol). And there is one binding site on the protein GST-Sare0718. We confirmed Asp preference of GST-Sare0718 by ITC. Therefore, Asp is the specific substrate. In addition, the experimental data indicates that the prediction system, “the specificity-conferring code”, is not suitable for marine actinomycetes. So it is urgent to set up a special predictive system for marine actinomycetes.
Źródło:: Acta Poloniae Pharmaceutica - Drug Research; 2018, 75, 6; 1287-1292
0001-6837
2353-5288
Pojawia się w:: Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 4.

Tytuł:: Badania FTIR-ATR i fluorescencyjne układów białkowo-lipidowych
FTIR-ATR and fluorescence studies of protein-lipid systems
Autorzy:: Litwińczuk-Mammadova, A.
Cieślik-Boczula, K.
Rospenk, M.
Powiązania:: https://bibliotekanauki.pl/articles/172158.pdf
Data publikacji:: 2017
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: spektroskopia FTIR-ATR
spektroskopia fluorescencyjna
anizotropia
efekt REES
wygaszanie fluorescencji
model stanów dyskretnych Trp
sonda fluorescencyjna
białko
lipid
FTIR-ATR spectroscopy
fluorescence spectroscopy
anisotropy
REES effect
fluorescence quenching
fluorescent probes
protein
Opis:: Lipid-protein systems paly curtail roles in living systems [49]. Hence, a determination of their structure at different levels of organization is still one of the most important tasks in many research projects. A study of lipid-protein systems is based on many physicochemical techniques, such as spectroscopy of FTIR, Raman, fluorescence, NMR, EPR, as well as DLS, DSC and TEM methods. In the presented paper tow of the most frequently used methods, that is FTIR and fluorescence spectroscopy, will be discussed in details. They are characterized by a relatively low cost of sample preparation, a short measuring time, and they give a huge number of structural and physicochemical information about lipid-protein systems. In the FTIR-ATR spectroscopy many of vibrational bands are commonly used as very precise vibrational indicators of structural changes in lipids and proteins (Fig. 1) [1–6]. They allows to characterize lipid and protein components separately in mixed systems. Additionally, structural changes in lipid membranes can be monitored in one FTIR-ATR experiment simultaneously in a region of hydrophilic lipid head-groups (Fig. 5) [17, 18], in a hydrophobic part composed of hydrocarbon lipid chains (see Figures 2 and 3) [7–9], and in a lipid membrane interface represented by ester lipid groups (Fig. 4) [4, 6, 11, 12]. A secondary structure of proteins and peptides in different experimental conditions can be defined in the FTIR-ATR spectroscopy on the base of amide I bands (Fig. 6 and Tabs 1, 2 and 3) [20–22]. A fluorescence spectroscopy is a complementary methods to FTIR spectroscopy in a study of lipid-protein systems. It competes information about time-dependent and very fast (in a scale of femtoseconds) structural processes in both lipids [41–45] and proteins [23, 27, 48]. The folding, denaturation, and aggregation of proteins and lipid membranes accompanied by changes in an order, packing and hydration of the system under study [23, 27, 41–45, 48].
Źródło:: Wiadomości Chemiczne; 2017, 71, 1-2; 109-132
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 5.

Tytuł:: Wykorzystanie fluorescencji do pomiaru stężenia tlenu w opakowaniach
Application of fluorescence in measuring oxygen concentration in packages
Autorzy:: Kozak, W.
Powiązania:: https://bibliotekanauki.pl/articles/1287042.pdf
Data publikacji:: 2011
Wydawca:: Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
Tematy:: czas wygaszania fluorescencji
sensor optyczny
opakowalnictwo
pakowanie w modyfikowanej atmosferze MAP
tlen
quenching time of fluorescence
optic sensor
packaging
modified atmosphere packaging (MAP)
measurement of oxygen content
Opis:: Nadmierna ilość tlenu w opakowaniu stanowi poważny problem z punktu widzenia jakości zapakowanych produktów, w szczególności spożywczych. Tlen jest bowiem w większości przypadków czynnikiem stymulującym niekorzystne zmiany objawiające się pogorszeniem się cech sensorycznych, obniżeniem wartości odżywczej, a nawet obniżeniem bezpieczeństwa zdrowotnego produktów. Stąd istotna jest możliwość kontrolowania ilości tlenu w opakowaniu, by móc ocenić warunki i pośrednio stan, w jakim znajduje się zapakowany produkt. Niniejsze opracowanie prezentuje jedną z najnowszych metod pomiaru ilości tlenu w opakowaniach, wykorzystującą do tego celu zjawisko fluorescencji. Wyjaśniona zostanie zasada działania przykładowego systemu, złożonego z fotoaktywnego sensora umieszczanego wewnątrz opakowania oraz sondy pomiarowej wzbudzającej wspomniany sensor i jednocześnie pozwalającej na pomiar intensywności fluorescencji sensora zależnej od ilości tlenu znajdującego się w jego otoczeniu. Przedstawione zostaną również potencjalne zastosowania wspomnianego systemu, daleko wykraczające poza możliwości dotychczas stosowanych metod pomiaru stężenia tlenu.
The surplus of oxygen content in the package is a serious problem considering the quality of packed products, in particular food products. In the majority of cases, oxygen is a factor stimulating unfavourable changes which are manifested by deterioration of sensory properties, reduction of nutritional value, and even reduction of health safety of food products. Thus, the possibility to control oxygen content in the package in order to assess conditions and indirectly the state of packed product is important. This paper presents one of brand new methods of oxygen measurements in the package involving the fluorescence phenomenon. The principle of operation of an exemplary system consisted of a photoactive sensor placed inside the package and the measurement probe exciting this sensor, and simultaneously enabling the measurement of the fluorescence intensity of the sensor depending on oxygen content in its surrounding, will be explained. Also, the potential applications of this system which are far beyond the possibilities of previously applied methods of oxygen concentration measurements will be presented.
Źródło:: Chemik; 2011, 65, 7; 627-632
0009-2886
Pojawia się w:: Chemik
Dostawca treści:: Biblioteka Nauki