DNA is known to have a double-helical structure. Do any other molecules have this structure?
2$\begingroup$ Probably also interesting to ask: was their molecular structure known before that of DNA? $\endgroup$– ShreevatsaRAug 13, 2017 at 19:25
$\begingroup$ Double Stranded RNA Actin Filament Collagen protein Starch is kind of similar too $\endgroup$– doc0abAug 24, 2017 at 16:41
A few examples:
A polymer of glucose that can form a double helix and functions primarily as energy storage in plants.
Filamentous actin forms a helical structure with two strands of polymerized g-actin. This is a structural component of the cytoskeleton.
Protein motif with a helical structure formed by two (or more) α-helices. Coiled coils are found in a diverse range of proteins from structural proteins like keratin to transcription factors like c-Fos.
A peptide-based antibiotic that has been shown to form membrane spanning double helices.
Yes, double-stranded RNA as found in some viruses.
1$\begingroup$ Do you know of any other such molecule? RNA is very similar to DNA, but is there a molecule that is very different from DNA and yet still has a double helix structure? $\endgroup$ Aug 11, 2017 at 16:29
3$\begingroup$ Yes, I thought you'd be only half satisfied with this answer. I do not know of any other molecules (but I am not a good chemist) but the answer may depend upon how different the structure of a molecule can be until you start considering its structure to really be different. $\endgroup$– Remi.bAug 11, 2017 at 16:34
The structural protein collagen consists of a triple helix of polypeptides. Whether this answers the question is arguable—you could say that the triple helix contains double helices. In any case, depending on what prompted your question, I thought it might be an interesting structure to consider.