  The similarity in the thermodynamic properties of two completely different
theoretical models for the helix-coil transition is examined critically. The
first model is an all-atomic representation for a poly-alanine chain, while the
second model is a minimal helix-forming model that contains no system
specifics. Key characteristics of the helix-coil transition, in particular, the
effective critical exponents of these two models agree with each other, within
a finite-size scaling analysis.
