Why 5'-3' and not 3'-5'
jmone at MARAUDER.MILLERSV.EDU
Fri Mar 27 08:38:37 EST 1998
In reply to Adams quip about evolutionaRy design and why the phosphate
doesn't hang off of the 3' carbon, I'm sure an answer could be found
in the thermodynamics of nucleotide synthesis, but perhaps a second
answer might be in the geometry of nucleic acids. The way DNA is
designed, the bond angles allow for the formation of a double helix
with relatively tight turns, and exquisite symmetry. This may allow
for efficient packaging of large pieces of nucleic acid inside very
tight spaces. Try drawing a double helix with the phosphate on the 3'
carbon, and see what you get.
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