排序方式: 共有25条查询结果,搜索用时 15 毫秒
21.
Yarmoluk SM Lukashov SS Losytskyy MY Akerman B Kornyushyna OS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(14):3223-3232
The interaction between double-stranded (ds) DNA and the cyanine dye Cyan 2 has been studied with spectral luminescence methods. Binding constant values have been determined by fluorescence titration and dye distribution in the two-phase system ethyl acetate-water (3.6 x 10(4) and 1.5 x 10(4) M(-1), respectively). Cyan 2 exhibits a small specificity for guanine-cytosine (GC) sequences in total DNA and synthetic polydeoxynucleotides poly(dA/dT) and poly(dGdC/dGdC). The DNA complexes with Cyan 2 are stable at high-ionic strength solution when NaCl is added. The dye molecule complexed with DNA is apparently shielded from the anionic quencher--iodide ion. The negative linear dichroism of the visible absorption band of aligned Cyan 2-DNA complexes indicates that the bound dye lies almost perpendicularly to the DNA helix axis. The linear dichroism of the absorption band at 260 nm suggests a considerable change in the DNA B-form. The results are consistent with an intercalative binding interaction between Cyan 2 and ds DNA. 相似文献
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Volkova KD Kovalska VB Losytskyy MY Fal KO Derevyanko NO Slominskii YL Tolmachov OI Yarmoluk SM 《Journal of fluorescence》2011,21(2):775-784
In present paper series of trimethine cyanines modified in 5,5′- or 6,6′- position with hydroxy- or methoxy- substituents
is studied for their ability to interact selectively with fibrillar formations. Processes of dye aggregation that accompany
this interaction were also investigated. Meso-methyl trimethynecyanines with 5,5′- methoxy (7519) and hydroxy (7515) substituents
strongly (up to 40 times) increase fluorescence intensity in the presence of fibrillar insulin, and also give noticeable fluorescent
response on the presence of various aggregated proteins (lysozyme, β-lactoglobulin, α-synuclein A53T). 7519 and 7515 dyes
can be used for fluorometric detection of fibrillar insulin at concentrations of approximately 1.5–120 microg/ml. For meso-ethyl
substituted dye 7514 the ability to form H- and J-aggregates upon interaction with insulin fibrils was suggested. The model
of the H- and J-aggregate packing in the protein fibrillar structure has been proposed. 相似文献
24.
Vladyslava B. Kovalska Mykhaylo Yu. Losytskyy Sergiy M. Yarmoluk Irit Lubitz Alexander B. Kotlyar 《Journal of fluorescence》2011,21(1):223-230
Two of earlier reported dsDNA sensitive cyanine dyes??monomethine Cyan 40 and meso-substituted trimethine Cyan 2 were studied for their ability to interact with non-canonical DNA conformations. These dyes were characterized by spectral-luminescent methods in the presence of G-quadruplex, triplex and dsDNA motifs. We have demonstrated that Cyan 2 binds strongly and preferentially to triple- and quadruple-stranded DNA forms that results in a strong enhancement of the dye fluorescence, as compared to dsDNA, while Cyan 40 form fluorescent complexes preferentially only with the triplex form. Highly fluorescent complexes of Cyan 2 with DNA triplexes and G-quadruplexes and Cyan 40 with DNA triplexes are very stable and do not dissociate during gel electrophoresis, leading to preferential staining of the above DNA forms in gels. The data presented point to the intercalation mechanism of the Cyan 2 binding to G4-DNA, while the complexes of Cyan 40 and Cyan 2 with triplex DNA are believed to be formed via groove binding mode. The Cyan dyes can provide a highly sensitive method for detection and quantification of non-canonical structures in genome. 相似文献
25.
Studies of Benzothiazole and Benzoselenazole Squaraines as Fluorescent Probes for Albumins Detection
Volkova KD Kovalska VB Losytskyy MY Bento A Reis LV Santos PF Almeida P Yarmoluk SM 《Journal of fluorescence》2008,18(5):877-882
Series of squaraine benzothiazole and benzoselenazole dyes were studied as possible fluorescent probes for the detection of
proteins, particularly albumins. It was shown that majority of the studied squaraines give significant fluorescent response
on the human serum albumin (HSA) and bovine serum albumin presence. For squaraine dyes with N-hexyl pendent groups (P-1, P-2, P-3, P-5) about 100−540-fold fluorescence intensity increase upon albumins addition was observed.
At the same time in presence of other proteins, namely insulin, avidin from hen egg white, immunoglobulin G (IgG), carbonic
anhydrase fluorescence enhancement values were considerably lower —up to 43 times in IgG presence. It was noted that generally,
squaraines with long N-hexyl pendent groups demonstrate higher emission increase values upon proteins addition comparing with their analogues with
short N-ethyl tails. It was shown that fluorescence intensity enhancement for benzothiazole squaraine dye P-3, relates linearly to
the HSA concentration over the wide range—from 0.2 to 500 μg/ml. Together with noticeable selectivity of this dye to albumins,
existence of wide dynamic range gives possibility to propose P-3 dye as probe for HSA quantification. 相似文献