singlehelical

singlehelical refers to a molecular structure that takes the form of a single spiral or helix. This is in contrast to double helices, such as the well-known structure of DNA, which consists of two intertwined helical strands. Single helical structures are found in various biological and chemical contexts.

One prominent example of a single helix is the structure of some proteins. Alpha-helices, a common secondary structure in proteins, are a type of single helix. In this arrangement, a polypeptide chain coils into a spiral, stabilized by hydrogen bonds between backbone atoms. Different types of viruses also exhibit single helical symmetry in their capsids, the protein shells that enclose their genetic material. For instance, the tobacco mosaic virus has a single helical arrangement of its coat proteins.

In the realm of nucleic acids, while DNA is famous for its double helix, RNA can exist in single-stranded forms that may adopt helical or partially helical conformations. These structures are often crucial for RNA function, such as in ribozymes or regulatory RNAs. The concept of single helicity is fundamental in understanding the three-dimensional organization of many biological macromolecules and their interactions.