  Previous research has shown a strong correlation of protein folding rates to
the native state geometry, yet a complete explanation for this dependence is
still lacking. Here we study the rate-geometry relationship with a simple
statistical physics model, and focus on two classes of model geometries,
representing ideal parallel and antiparallel structures. We find that the
logarithm of the rate shows an almost perfect linear correlation with the
"absolute contact order", but the slope depends on the particular class
considered. We discuss these findings in the light of experimental results.
