27
$\begingroup$

DNA is known to have a double-helical structure. Do any other molecules have this structure?

$\endgroup$
  • 2
    $\begingroup$ Probably also interesting to ask: was their molecular structure known before that of DNA? $\endgroup$ – ShreevatsaR Aug 13 '17 at 19:25
  • $\begingroup$ Double Stranded RNA Actin Filament Collagen protein Starch is kind of similar too $\endgroup$ – doc0ab Aug 24 '17 at 16:41
50
+500
$\begingroup$

A few examples:


Starch

A polymer of glucose that can form a double helix and functions primarily as energy storage in plants.

enter image description here

[image source]


f-Actin

Filamentous actin forms a helical structure with two strands of polymerized g-actin. This is a structural component of the cytoskeleton.

enter image description here

[image source]


Coiled Coil

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.

enter image description here

[image source]


Gramicidin

A peptide-based antibiotic that has been shown to form membrane spanning double helices.

enter image description here

[image source]

$\endgroup$
16
$\begingroup$

Yes, double-stranded RNA as found in some viruses.

$\endgroup$
  • 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? $\endgroup$ – The Riddler Aug 11 '17 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.b Aug 11 '17 at 16:34
12
$\begingroup$

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.

Collagen-like peptide triple helix consisting of three peptide molecules (orange, blue, purple)

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.