Skip Navigation

This Article
Right arrow Print PDF (888K)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Langowski, J.
Right arrow Articles by Sänger, H. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Langowski, J.
Right arrow Articles by Sänger, H. L.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nucleic Acids Research, 1978, Vol. 5, No. 5 1589-1610
© 1978

Articles

Common structural features of different viroids: serial arrangement of double helical sections and internal loops

Jörg Langowski+, Karsten Henco, Detlev Riesner* and Heinz Ludwig Sänger**

Institut für Organische Chemie und Biochemie, Technische Hochschule Petersenstr. 22, D 6100 Darmstadt, and Institut für Klinische Biochemie und Physiologische Chemie Medizinische Hochschule Hannover, GFR

*to whom correspondence should be addressed

Received February 6, 1978.

The thermodynamic parameters of five different highly purified viroid "species" were determined by applying UV-absorption melting analysis and temperature jump methods. Their thermal denaturation proved to be a highly cooperative process with mid-point-temperatures (Tm) between 48.5 and 51°C in 0.01 M sodium cacodylate, 1 mM EDTA, pH 6.8. The values of the apparent reaction enthalpies of the different viroid species range between 3,140 and 3,770 kJ/mol. Although the cooperativity is as high as found in homogeneous RNA double helices the Tm-value of viroid melting is more than 30°C lower than in the homogeneous RNA. In order to explain this deviation, melting curves were simulated for different models of the secondary structure of viroids using literature values of the thermodynamic parameters of nucleic acids. Our calculations show that the following refinement of our earlier model is in complete accordance with the experimental data: In their native conformation viroids exist as an extended rodlike structure characterized by a series of double helical sections and internal loops. In the different viroid species 250–300 nucleotides out of total 350 nucleotides are needed to interprete the thermodynamic behaviour.

+present address: Stanford University, School of Medicine, Dept. of Biochemistry, Stanford, Calif. 94305

**Arbeitsgruppe Pflanzenvirologie Justus-Liebig -Universität, Schubertstr. 1, D 6300 Giessen, GFR


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 ScienceHome page
T. Diener
Viroids: structure and function
Science, August 31, 1979; 205(4409): 859 - 866.
[Abstract] [PDF]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.