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- Egholm, M., et al.
(författare)
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PNA HYBRIDIZES TO COMPLEMENTARY OLIGONUCLEOTIDES OBEYING THE WATSON-CRICK HYDROGEN-BONDING RULES
- 1993
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 365:6446, s. 566-568
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Tidskriftsartikel (refereegranskat)abstract
- DNA ANALOGUES are currently being intensely investigated owing to their potential as gene-targeted drugs1-3. Furthermore, their properties and interaction with DNA and RNA could provide a better understanding of the structural features of natural DNA that determine its unique chemical, biological and genetic properties3,4. We recently designed a DNA analogue, PNA, in which the backbone is structurally homomorphous with the deoxyribose backbone and consists of N-(2-aminoethyl)glycine units to which the nucleobases are attached5-9. We showed that PNA oligomers containing solely thymine and cytosine can hybridize to complementary oligonucleotides, presumably by forming Watson-Crick-Hoogsteen (PNA)2-DNA triplexes, which are much more stable than the corresponding DNA-DNA duplexes5-7, and bind to double-stranded DNA by strand displacement5,8. We report here that PNA containing all four natural nucleobases hybridizes to complementary oligonucleotides obeying the Watson-Crick base-pairing rules, and thus is a true DNA mimic in terms of base-pair recognition.
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| 2. |
- Baert, L, et al.
(författare)
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Clinical Fluorescence Diagnosis of Human Bladder-carcinoma Following Low-dose Photofrin Injection
- 1993
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Ingår i: Urology. - : Elsevier BV. - 1527-9995 .- 0090-4295. ; 41:4, s. 322-330
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Tidskriftsartikel (refereegranskat)abstract
- A point-monitoring fluorescence diagnostic system based on a low-energy pulsed laser, fiber transmission optics, and an optical multichannel analyzer was used for diagnosis of patients with bladder malignancies. Twenty-four patients with bladder carcinoma, carcinoma in situ, and/or dysplasia were injected with hematoporphyrin derivative, Photofrin, 0.35 or 0.5 mg/kg body weight, forty-eight hours prior to the investigation. The ratio between the red sensitizer emission and the bluish tissue autofluorescence provided excellent demarcation between papillary tumors and normal bladder wall. Certain cases of dysplasia also could be differentiated from normal mucosa. Benign exophytic lesions such as malakoplakia appeared different from malignant tumors in fluorescence. Flat suspicious bladder mucosa such as seen in infectious diseases or after radiation therapy appeared normal on fluorescence.
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| 3. |
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| 4. |
- Berg, Roger, et al.
(författare)
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Time-resolved tranillumination imaging
- 1993
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Ingår i: Medical Optical Tomography: Functional Imaging and Monitoring. ; , s. 397-424
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Bokkapitel (refereegranskat)
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| 5. |
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| 6. |
- Kim, Seog K., et al.
(författare)
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RIGHT-HANDED TRIPLEX FORMED BETWEEN PEPTIDE NUCLEIC-ACID PNA-T(8) AND POLY(DA) SHOWN BY LINEAR AND CIRCULAR-DICHROISM SPECTROSCOPY
- 1993
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 115:15, s. 6477-6481
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Tidskriftsartikel (refereegranskat)abstract
- The binding of an eightmer of peptide nucleic acid, H-T8-Lys-NH2 (=PNA-T8), to a polynucleotide, poly(dA), was studied by flow linear dichroism (LD) and circular dichroism (CD) spectroscopy. Whereas the single stranded DNA, due to its high flexibility, does not display any measurable LD signal when subjected to shear flow, the complex with PNA does. A titration shows that saturation occurs at a stoichiometry of two PNA thymine bases per DNA adenine base, indicating the formation of a triplex PNA2-DNA complex. The persistence length of the adduct remains small up to relatively high stoichiometries (above 1:1 T:A) indicating that no significant amounts of PNA:DNA duplex are formed. Instead triplex stretches seem to form surrounded by flexible parts of single stranded poly(dA). Upon approaching the stoichiometry 2:1 of T:A the LD increases dramatically demonstrating that the stiffness of the PNA-DNA triplex arises from base-base contacts preventing bending of the chain. It is also inferred that the main stiffness of duplex DNA very probably has a similar origin and is not primarily a result of the increased phosphate-phosphate repulsion. Circular dichroism spectra support the conclusion that a triplex is formed as the only PNA-DNA complex and that it is a right-handed helix. The wavelength dependence of the reduced linear dichroism shows that the inclination of the bases from perpendicularity relative to the helix axis is small. The base conformation of the poly(dA)[PNA-T8]2 triplex is very similar to that of the conventional poly(dA)[poly(dT)]2 triplex.
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