Dynamic Light Scattering and Atomic Force Microscopy are the two methods used to evaluate the size of plasmids. Are plasmids dimensions strictly within 1 to 100 Angstroms ?

LabGenius, pDraw32, Geneious, Lasergene, MacVector, GeneConstructionKit, ApE, Clone Manager, VectorFriends, and Vector NTI handle plasmid maps - their libraries may already have dimensions of plasmids.

Plasmids 101: A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules; however, plasmids are sometimes present in archaea and eukaryotic organisms.

AFM would be my first thought if the equipment is available to you.

Thank you for your responses; I was actually hoping for a mathematical formula to estimate the diameter (apologies, I should have been more clear in my question). Currently I'm using the rms radius of gyration (one third the square root of the number of bp times the persistence length of dsDNA) to estimate the plasmids' size but was wondering if there was perhaps a more accurate way to calculate this.

Thanks again!

Hi Jill, thanks for the clarification. I've sent you the name of a biophysicist who I believe can help you.

For an estimate of the size otr diameter, it would help to know the constituent atoms and structure of the molecule. In that case you can use approximate bond lengths to guess a size.

By using the tools in stochastic geometry, you can estimate the diameter of R2, if estimating them is enough for you, please send figures or illustration to see the shape of them. Thank you. Mehmet