In the world of biomolecules such as proteins and the hereditary nucleic acids DNA and RNA, three-dimensional structure determines function. Analysis of the passage of such molecules through nanopores offers a relatively new, but highly promising, technique for obtaining information about their spatial conformations. However, interactions between the test molecules and the proteins used as pores have so far hindered quantitative analysis of the behavior of even simply structured molecules within nanopores. This problem must be solved before the technique can be routinely used for structure determination. In a project carried out under the auspices of the Cluster of Excellence "Nanosystems Initiative Munich" (NIM), researchers led by LMU physicist Professor Ulrich Gerland and Professor Friedrich Simmel (Technical University of Munich) have developed a new method that depends on the analysis of reverse translocation through asymmetric pores, which minimizes the interference caused by interactions with the pore material itself. This approach has enabled the team to construct a theoretical model that allows them to predict the translocation dynamics of nucleic acids that differ in their nucleotide sequences.
The nucleic acids RNA and DNA both belong to the class of molecules known chemically as polynucleotides. Both are made up of strings of four basic types of building blocks called nucleotides, which fall into two complementary pairs. In their single-stranded forms, DNA and RNA can fold into what are called secondary structures, as complementary nucleotides in the sequence pair up, forcing the intervening segments to form loops. If the single-stranded loop is very short, the secondary structure is referred to as a hairpin. As in the case of proteins, the secondary structures of nucleic acids influence their biochemical functions. The elucidation of the secondary structure of nucleic acid sequences is therefore of great interest.
|Contact: Dr. Katrhin Bilgeri|