What is the diameter of each type of deoxyribonucleotide (if the types are significantly different in diameter, if they are fairly similar one value would suffice)? I.e., if a hole was to be created through which only a single deoxyribonucleotide could pass at a time, how small would it have to be?
1 Answer
DNA is about 20 angstroms wide, so each of the two strand is about 10 angstroms wide. That width is the average between a larger purine unit and smaller pyrimidine unit, so let's round up to 12 or 13 angstroms for the larger unit.
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$\begingroup$ While this answer gives a reasonable approximation for nucleotides constrained in a double helix, it should be noted that nucleotides have conformational isomers and they could potentially be smaller when free in solution. Purines especially can form a syn conformation which is much more compact than the anti conformation found in B-DNA. $\endgroup$ Jun 20, 2017 at 0:32