Aspectos estructurales de la interrelación entre lípidos y proteínas en membranas.

Abstract

The interpretation of the processes that occur in relation with biological membranes or membrane-bound organeles, is intimately related with the organization of these membranes, thus, advances in the knowledge of the structure and molecular relationships are of foremost importance to the understanding of their biological properties. We have applied the freeze-etching to a model membrane (a complex lipid bilayer), a novel method that produces no chemical alteration to the bilayers. Observations of Platinum - or Chromium -n- shadowed replicas under the Electron Microscope show that hemocyanin and/or their subunits penetrate in the depth of the bilayer and appear themselves covered on both sides by the lipids. The application of freeze-etching to photoreceptors demonstrates that the disc membrane have an asymmetrical protein distribution. In conclusion: the current concept of biological membrane structure cannot be applied fully to our membrane model and probably neither to any type of membrane; in fact, each active membrane has an peculiar organization to be understood in terms of its biological function.