Biophysical Journal 47: 285-293 (1985)
© 1985 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Downer, N W Search for Related Content PubMed PubMed Citation Articles by Downer, N W

Cross-linking of dark-adapted frog photoreceptor disk membranes. Evidence for monomeric rhodopsin.

ABSTRACT

A model for random cross-linking of identical monomers diffusing in a membrane was formulated to test whether rhodopsin's cross-linking behavior was quantitatively consistent with a monomeric structure. Cross-linking was performed on rhodopsin both in intact retinas and in isolated rod outer segment (ROS) membranes using the reagent glutaraldehyde. The distribution of covalent oligomers formed was analyzed by SDS-polyacrylamide gel electrophoresis and compared to predictions for the random model. A similar analysis was made for ROS membranes cross-linked by diisocyanatohexane and retinas cross-linked by cupric ion complexed with o-phenanthroline. Patterns of cross-linking produced by these three reagents are reasonably consistent with the monomer model. Glutaraldehyde was also used to cross-link the tetrameric protein aldolase in order to verify that cross-linking of a stable oligomer, under conditions comparable to those used for ROS, yielded the pattern predicted for a tetrameric protein having D2 symmetry. This pattern is markedly different from the one for a random-collision model. Moreover, a comparison of rates showed that aldolase cross-linking with glutaraldehyde is significantly faster than cross-linking of membrane-bound rhodopsin. It is concluded that rhodopsin is monomeric in dark-adapted photoreceptor membranes and that the observed cross-linking results from collisions between diffusing rhodopsin molecules.

This article has been cited by other articles:

				T. C. Edrington 5th, M. Bennett, and A. D. Albert Calorimetric Studies of Bovine Rod Outer Segment Disk Membranes Support a Monomeric Unit for Both Rhodopsin and Opsin Biophys. J., September 15, 2008; 95(6): 2859 - 2866. [Abstract] [Full Text] [PDF]

				R. Medina, D. Perdomo, and J. Bubis The Hydrodynamic Properties of Dark- and Light-activated States of n-Dodecyl {beta}-D-Maltoside-solubilized Bovine Rhodopsin Support the Dimeric Structure of Both Conformations J. Biol. Chem., September 17, 2004; 279(38): 39565 - 39573. [Abstract] [Full Text] [PDF]

				C. G. Bevans, M. Kordel, S. K. Rhee, and A. L. Harris Isoform Composition of Connexin Channels Determines Selectivity among Second Messengers and Uncharged Molecules J. Biol. Chem., January 30, 1998; 273(5): 2808 - 2816. [Abstract] [Full Text] [PDF]