Molecular properties involved in the effects of steroids on membrane biophysical state

WENZ J.J.

Villa Carlos Paz

Congreso; XLII Reunión Anual de la Sociedad Argentina de Biofísica; 2013

SAB (Sociedad Argentina de Biofísica)

In order to learn about the factors that govern the effects of steroids on the physical state of membranes, a library of 82 steroids was studied regarding their ordering, rigidifying, condensing and/or raft promoting activity on membranes, concurrently with several molecular properties. Steroids were classified according to their reported activity on membranes into one of two categories by defining a dichotomous variable (0´s and 1´s). Each molecular structure was subjected to geometry optimization by means of a semi-empirical procedure (AM1) and several molecular descriptors were next computed for the optimized low energy conformations. The obtained data were analyzed by means of logistic regression and mean contrasting. Comparing steroids displaying ordering, rigidifying, condensing and/or raft promoting activity with their counterparts having the opposite effect, substantial differences were found in the partition coefficients (octanol-water), surface area, volume, number of rotatable bonds (mostly present in the carbon alkyl side-chain), molar refractivity and molecular weight. Despite the intrinsic correlation between the molecular properties, the results collectively point toward a positive correlation between steroids lipophylicity and their ordering, rigidifying, condensing and/or raft promoting effects on bilayers.