  Davydov's model of solitons in alpha-helix protein chains is shown to display
features of self-organized criticality (SOC), i.e., power law behaviour of
correlations in space and 1/f-noise, as a consequence of considering random
peptide group displacements from their (periodic) equilibrium positions along a
chain. This may shed light on a basic mechanism leading to obtain flicker noise
in alpha-helix protein chains and to predict a SOC regime in biomolecular
structures from first principles. We believe our treatment of 1/f noise to be
of some relevance to recent findings due to Voss on DNA [Phys. Rev. Lett. 68,
3805 (1992)].
