# Estimate of Unfolded state Accessible Surface Area

This is a form that allows you to enter a sequence and compute
an estimate of the accessible surface area of a protein in the
unfolded state

## Description

The surface area buried by a protein in the native (folded)
state is widely used as a measure of the contribution of the
hydrophobic effect. While the accessible surface area of the folded
state is readily computed from the experimentally determined conformation,
the surface area in the unfolded state has to be estimated.
Usually, the surface area in the unfolded
state is computed as the sum of the accessible surface area of
each residue in an extended tri-peptide. This procedure is
sub-optimal and over estimates the accessible surface area.
The method used here, uses estimated
lower and upper bounds for the surface area of the residue in
the unfolded state based both on an analysis of known structures
as well as hard sphere Monte Carlo simulations, and is thought to
be a better approximation of the unfolded state surface area.
### References

- Creamer, T.P., Srinivasan, R. and Rose, G.D.
Modeling unfolded states of peptides and proteins.
Biochemistry 34: 16245-16250, 1995.
- Creamer, T.P., Srinivasan, R. and Rose, G.D.
Modeling unfolded states of proteins and peptides. II. Backbone
solvent accessibility.
Biochemistry 36: 2832-2835, 1997.