Results found: 3

Number of results on page

Search results

Search:
in the keywords: fluorescence quenching

Sort By:

Limit search:

Interaction of three Caenorhabditis elegans isoforms of translation initiation factor eIF4E with mono- and trimethylated mRNA 5' cap analogues.

100%

Stachelska A., Wieczorek Z., Ruszczyńska K., Stolarski R., Pietrzak M., Lamphear B. J., Rhoads R. E., Darżynkiewicz E., Jankowska-Anyszka M.

2002

vol. 49

issue 3

671-682

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.

Fluorescence imaging of hybrid nanostructures composed of natural photosynthetic complexes and reduced graphene oxide

86%

Twardowska M., Chomicki D., Kamińska I., Niedziółka-Jönsson J., Maćkowski S.

Nanospectroscopy

2014

vol. 1

issue 1

Herein, we describe the results of fluorescence microscopy imaging of peridinin-chlorophyll-protein (PCP) photosynthetic complex mixed with reduced graphene oxide (rGO). Upon incorporation of rGO the fluorescence image of PCP changes substantially from one characterized by uniform intensity towards a more complex pattern. The isolated bright spots feature up to ten times higher emission intensity compared to the fluorescence of PCP in the reference sample, where no rGO was added. The number of the bright spots increases with increasing rGO concentration. At the same time the fluorescence intensity away from the bright spots in the PCP/rGO hybrid system is quenched in comparison to the PCP – only reference.

In vitro fluorescence studies of transcription factor IIB-DNA interaction

86%

Górecki A., Figiel M., Dziedzicka-Wasylewska M.

2015

vol. 62

issue 3

413-421

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.

Refine search results

2 Acta Biochimica Polonica

1 Nanospectroscopy

2 2015

1 2002

1 Chomicki D.

1 Darżynkiewicz E.

1 Dziedzicka-Wasylewska M.

1 Figiel M.

1 Górecki A.

1 Jankowska-Anyszka M.

1 Kamińska I.

1 Lamphear B. J.

1 Maćkowski S.

1 Niedziółka-Jönsson J.

1 Pietrzak M.

1 Rhoads R. E.

1 Ruszczyńska K.

1 Stachelska A.

1 Stolarski R.

1 Twardowska M.

1 Wieczorek Z.

Search results

Interaction of three Caenorhabditis elegans isoforms of translation initiation factor eIF4E with mono- and trimethylated mRNA 5' cap analogues.

Fluorescence imaging of hybrid nanostructures composed of natural photosynthetic complexes and reduced graphene oxide

In vitro fluorescence studies of transcription factor IIB-DNA interaction