3 research outputs found
К вопросу расчетного определения пускового тока электродвигателей забойных машин и тока короткого замыкания в участковых сетях низкого напряжения
Irregular spectral position of E ¦¦ c component of polarized photoluminescence from m-plane InGaN/GaN multiple quantum wells grown on LiAlO2
A neutral DNA sequence-selective vector for interaction studies: Fluorescence binding experiments directed towards a carbohydrate-DNA carrier
The distamycin-type γ-linked covalent dimer -Py-γ-Py-Ind
has been shown to be a neutral selective vector capable of
transporting recognition elements to the minor groove of
DNA for further structural studies. Comparison of fluorescence
binding constants of the complexes formed by the vectors
(R-Py-γ-Py-Ind 1 and 3) with ct-DNA and poly(dA-dT)
showed that -Py-γ-Py-Ind is a neutral (–ATAT–)-selective vector.
We also provide experimental data that show that the
vector can be used as a sugar-carrier to the DNA. Thus, modifying
the vector at the C terminus with sugars of different
configurations (4–7 D vs. 8 L), and with both α- and β-linkages
(5 and 4, respectively) to the oligoamide fragment provides
efficient DNA binders (Ka = 1.1 104 to 3.2 105 M–1). Moreover,
the sugar residue is able to modulate the binding to the
different DNA polymers studied and, even more relevantly,the sugar contributes to the selectivity of binding: β-D-Gal-
Py-γ-Py-Ind (6) is the most selective –ATAT–sugar–oligoamide
ligand {ΔΔG° 6 [poly(dA-dT) – ct-DNA] = –4.0 kcal
mol–1}. We have used fluorescence quantum yield values to
ensure the presence of similar free state conformation for ligands
1–8 and we can thus correlate the differences in the
measured binding energies with the changes in the shape of
the structural elements. Finally, we have demonstrated that
the sequence-selective sugar carrier makes a 1:1 complex
with the Drew–Dickerson oligonucleotide dodecamer, thus
opening the road to more detailed structural and thermodynamic
studies of sugar-oligoamide DNA short oligonucleotide
complexes in solution.Financial support for this work was provided by the Ministerio de
Educación y Ciencia (MEC) (BQU2003-03550-C03-02 and
CTQ2006-10874-C02-02) and a European Research Training Network
(RTN) project (HPRN-CT-2002-00190). P. P. is grateful to
the Consejo superior de Investigaciones Científicas for an I3P predoctoral
fellowship. S. A. thanks RTN and MEC for a Juan
de la Cierva postdoctoral contract.Peer reviewe