For a single loop, the entropy varies logarithmically with the number of residues
This entropy formula corresponds to a power-law distribution
The loop entropy may also vary with the position of the contacting residues.
Residues near the ends of the polymer are more likely to contact (quantitatively, have a lower
) than those in the middle (i.e., far from the ends), primarily due to excluded volume effects.
The loop entropy formula becomes more complicated with multiples loops, but may be determined for a Gaussian polymer using a matrix method developed by Wang and Uhlenbeck.
equal the number of common residues between loops
The entropy of making the specified contacts equals As an example, consider the entropy lost upon making the contacts between residues 26 and 84 and residues 58 and 110 in a polymer (cf.
The first and second loops have lengths 58 (=84-26) and 52 (=110-58), respectively, and they have 26 (=84-58) residues in common.
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