Electro-Optical Instrumentation Systems with Their Data Acquisition and Treatment

Houssier, Claude; O’Konski, Chester T.

doi:10.1007/978-1-4684-3914-4_15

Cited by 32 publications

(20 citation statements)

References 34 publications

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“…1977;Houssier, 1981). The pulse generator and the computerized optical measurement system used for linear dichroism have been previously described (Houssier and O'Konski, 1981). The electric field pulses in the range 0-13 kV/cm were applied to the samples in a 10mm optical pathlength Kerr cell with a distance between the platinum electrodes of 1.5 mm.…”

Section: Electric Linear Dichroism (Eld)mentioning

confidence: 99%

Drug—DNA sequence‐dependent interactions analysed by electric linear dichroism

Bailly

Hénichart

Colson

et al. 1992

J of Molecular Recognition

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The interactions between 20 drugs and a variety of synthetic DNA polymers and natural DNAs were studied by electric linear dichroism (ELD). All compounds tested, including several clinically used antitumour agents, are thought to exert their biological activities mainly by virtue of their abilities to bind to DNA. The selected drugs include intercalating agents with fused and unfused aromatic structures and several groove binders. To examine the role of base composition and base sequence in the binding of these drugs to DNA, ELD experiments were carried out with natural DNAs of widely differing base composition as well as with polynucleotides containing defined alternating and non-alternating repeating sequences, poly(dA).poly(dT), poly(dA-dT).poly(dA-dT),poly(dG).poly(dC) and poly(dG-dC).poly(dG-dC). Among intercalating agents, actinomycin D was found to be by far the most GC-selective. GC selectivity was also observed with an amsacrine-4-carboxamide derivative and to a lesser extent with methylene blue. In contrast, the binding of amsacrine and 9-aminoacridine was practically unaffected by varying the GC content of the DNAs. Ethidium bromide, proflavine, mitoxantrone, daunomycin and an ellipticine derivative were found to bind best to alternating purine-pyrimidine sequences regardless of their nature. ELD measurements provided evidence for non-specific intercalation of amiloride. A significant AT selectivity was observed with hycanthone and lucanthone. The triphenyl methane dye methyl green was found to exhibit positive and negative dichroism signals at AT and GC sites, respectively, showing that the mode of binding of a drug can change markedly with the DNA base composition. Among minor groove binders, the N-methylpyrrole carboxamide-containing antibiotics netropsin and distamycin bound to DNA with very pronounced AT specificity, as expected. More interestingly the dye Hoechst 33258, berenil and a thiazole-containing lexitropsin elicited negative reduced dichroism in the presence of GC-rich DNA which is totally inconsistent with a groove binding process. We postulate that these three drugs share with the trypanocide 4',6-diamidino-2-phenylindole (DAPI) the property of intercalating at GC-rich sites and binding to the minor groove of DNA at other sites. Replacement of guanines by inosines (i.e., removal of the protruding exocyclic C-2 amino group of guanine) restored minor groove binding of DAPI, Hoechst 33258 and berenil. Thus there are several cases where the mode of binding to DNA is directly dependent on the base composition of the polymer. Consequently the ELD technique appears uniquely valuable as a means of investigating the possibility of sequence-dependent recognition of DNA by drugs.

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Section: Electric Linear Dichroism (Eld)mentioning

confidence: 99%

Drug—DNA sequence‐dependent interactions analysed by electric linear dichroism

Bailly

Hénichart

Colson

et al. 1992

J of Molecular Recognition

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“…Electric linear dichroism measurements were performed using a computerized optical measurement system built by C. Houssier (Houssier and O'Konski, 1981). The procedures outlined previously were followed (Houssier, 1981).…”

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confidence: 99%

Recognition of Specific Sequences in DNA by a Topoisomerase I Inhibitor Derived from the Antitumor Drug Rebeccamycin

et al. 1998

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We investigated the interaction with DNA of two synthetic derivatives of the antitumor antibiotic rebeccamycin: R-3, which is a potent topoisomerase I inhibitor and contains a methoxyglucose moiety appended to the indolocarbazole chromophore, and its aglycone, R-4. Spectroscopic measurements indicate that R-3 intercalates into DNA and that its carbohydrate domain contributes significantly to reinforce the affinity for DNA. Two complementary ligation assays concur that R-3, but not its aglycone counterpart, exerts a significant effect on the curvature and/or the flexibility of DNA. The sugar moiety may be responsible for preferential binding of R-3 to circular (or bent) DNA molecules as opposed to linear DNA fragments. The sequence selectivity of binding to DNA has been studied thoroughly by footprinting with DNase I and two other nucleases. The glycosylated compound is highly selective for nucleotide sequences containing GpT (ApC) and TpG (CpA) steps. The derivative lacking the sugar moiety on the indolocarbazole chromophore binds at essentially identical sites but with considerably lower affinity, so it seems that the chromophore rather than the carbohydrate is responsible for the preferential binding to sequences surrounding GpT and TpG steps. The influence of the exocyclic substituents present on the bases at the recognition sites (i.e., the 2-amino group of guanine and the 5-methyl group of thymine) was evaluated using two series of modified DNA molecules prepared by polymerase chain reaction containing inosine and/or 2,6-diaminopurine and uridine and/or 5-methylcytosine residues. The introduction of the amino group onto purine residues or the addition of a methyl group to pyrimidine residues suffices to create new drug binding sites. Therefore, unlike most DNA-binding small molecules, the rebeccamycin analogue seems to be highly sensitive to any modification of the exocyclic substituents on the bases in both the major and minor grooves of the double helix. The footprinting profiles with the different DNA fragments bear a remarkable resemblance to those determined for nogalamycin and bisnaphthalimide compounds known to recognize their preferred GpT and TpG sites via intercalation from the major groove. The unique DNA binding characteristics of the rebeccamycin analogue correlate well with its inhibitory effects on topoisomerase I .The camptothecin derivatives irinotecan (CPT-11) and topotecan recently introduced in cancer chemotherapy are arguably the best characterized topoisomerase I poisons (Pommier and Tanizawa, 1993). These drugs interfere with the breakage-rejoining reaction by stabilizing a covalent topoisomerase I/DNA intermediate (usually referred to as cleavable complex), which can be detected by the appearance of DNA strand breaks on denaturation of the protein with a detergent. So far, relatively few other drugs have been shown to promote topoisomerase I-mediated DNA cleavage. Intoplicine, saintopins, and related naphthacene-dione antibiotics as well as alkaloids such as bulgarein and cor...

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“…The above T-Jump assembly was connected to a data acquisition and treatment system used for electro-optical measurements and described in detail elsewhere (22,23). The changes of absorbance were calculated from the 1024 data points signals transferred from the transient recorder to a minicomputer (ModComp 11/10; Modular Computer Systems, Fort Lauderdale) using the equation:…”

Section: Temperature-jump Experimentsmentioning

confidence: 99%

“…b) characteristic relaxation times tau(x)=t(x)/x (with x=O.S, 1, 1.5, 2, 2.5, 3 ... ) were determined along the normalized relaxation curve for relative decays to Downloaded by [Rutgers University] at 12:17 11 April 2015 exp( -x) (22,23). For a monoexponential relaxation process all these decay times should be identical and equal to tau, the unique relaxation time of the process.…”

Section: Analysis Of the Relaxation Signalsmentioning

confidence: 99%

Temperature Jump Relaxation Studies on the Interactions Between Transfer RNAs with Complementary Anticodons. The Effect of Modified Bases Adjacent to the Anticodon Triplet

Houssier¹,

Grosjean²

1985

Journal of Biomolecular Structure and Dynamics

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We have used the temperature-jump relaxation technique to determine the kinetic and thermodynamic parameters for the association between the following tRNAs pairs having complementary anticodons: tRNA(Ser) with tRNA(Gly), tRNA(Cys) with tRNA(Ala) and tRNA(Trp) with tRNA(Pro). The anticodon sequence of E. coli tRNA(Ser), GGA, is complementary to the U*CC anticodon of E. coli tRNA(Gly(2] (where U* is a still unknown modified uridine base) and A37 is not modified in none of these two tRNAs. E. coli tRNA(Ala) has a VGC anticodon (V is 5-oxyacetic acid uridine) while tRNA(Cys) has the complementary GCA anticodon with a modified adenine on the 3' side, namely 2-methylthio N6-isopentenyl adenine (mS2i6A37) in E. Coli tRNA(Cys) and N6-isopentenyl adenine (i6A37) in yeast tRNA(Cys). The brewer yeast tRNA(Trp) (anticodon CmCA) differs from the wild type E. coli tRNA(Trp) (anticodon CCA) in several positions of the nucleotide sequence. Nevertheless, in the anticodon loop, only two interesting differences are present: A37 is not modified while C34 at the first anticodon position is modified into a ribose 2'-O methyl derivative (Cm). The corresponding complementary tRNA is E.coli tRNA(Pro) with the VGG anticodon. Our results indicate a dominant effect of the nature and sequence of the anticodon bases and their nearest neighbor in the anticodon loop (particularly at position 37 on the 3' side); no detectable influence of modifications in the other tRNA stems has been detected. We found a strong stabilizing effect of the methylthio group on i6A37 as compared to isopentenyl modification of the same residue. We have not been able so far to assess the effect of isopentenyl modification alone in comparison to unmodified A37. The results obtained with the complex yeast tRNA(Trp)-E.coli tRNA(Pro) also suggest that a modification of C34 to Cm34 does not significantly increase the stability of tRNA(Trp) association with its complementary anticodon in tRNA(Pro). The observations are discussed in the light of inter- and intra-strand stacking interactions among the anticodon triplets and with the purine base adjacent to them, and of possible biological implications.

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Electro-Optical Instrumentation Systems with Their Data Acquisition and Treatment

Cited by 32 publications

References 34 publications

Drug—DNA sequence‐dependent interactions analysed by electric linear dichroism

Drug—DNA sequence‐dependent interactions analysed by electric linear dichroism

Recognition of Specific Sequences in DNA by a Topoisomerase I Inhibitor Derived from the Antitumor Drug Rebeccamycin

Temperature Jump Relaxation Studies on the Interactions Between Transfer RNAs with Complementary Anticodons. The Effect of Modified Bases Adjacent to the Anticodon Triplet

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