Influence of organotin compounds on phosphatidylserine membranes

Abstract

Organotin compounds are widely distributed toxicants. They are membrane-active molecules with broad biological toxicity. We have studied the interaction of tributyltin and triphenyltin with phosphatidylserine model membranes using differential scanning calorimetry, infrared spectroscopy and X-ray diffraction techniques. Organotin compounds produced a broadening of the gel to the liquid-crystalline phase transition of the phospholipid and a shifting of the phase transition temperature to lower values. Infrared spectroscopy experiments showed that tributyltin exerted a fluidizing effect on the apolar part of the bilayer, and that both tributyl-and triphenyltin interact with the interfacial region of the bilayer, making the carbonyl groups less accessible to water. As seen by X-ray diffraction experiments, organotin compounds were unable to change the bilayer macroscopic organization of the phospholipid, but they were able to reduce the long-range order of the multibilayer system and to disorder the packing of the phospholipid molecules. The observed interaction between organotin compounds and phosphatidylserine membranes promotes physical perturbations that could affect membrane function and may mediate some of their toxic effects.

Biological activity studies on organotin(IV)n+ complexes and parent compounds

“…The observed interaction between organotin(IV) compounds and phosphatidylserine promotes physical perturbations, which could affect membrane function and may mediate some of their toxic effects [112].…”

Location and Effects of an Antitumoral Catechin on the Structural Properties of Phosphatidylethanolamine Membranes

“…We used Nickel-filtered Cu Kα X-rays generated by a Philips PW3830 X-ray Generator operating at 50 kV and 30 mA, and a modified Kratky camera (MBraum-Graz-Optical Systems, Graz, Austria) equipped with two coupled linear position sensitive detectors (PSD, MBraum, Garching, Germany) monitoring the s-ranges (s = 2 sinθ/λ, 2θ = scattering angle, λ = 1.54 Å) between 0.0075–0.7 Å −1 and 0.20–0.29 Å −1 respectively as already defined [47]. We centrifuged (13,000 rpm) multilamellar vesicles containing 15 mg DMPE and the proper amount of TMCG and the obtained sediments were measured in a steel holder in contact with a Peltier unit, using cellophane windows.…”

Interaction of trialkyltin(IV) chlorides with sarcoplasmic reticulum calcium ATPase

“…[17,18] Triorganotin compounds affect the degree of hydration of the carbonyl moiety of phosphatidylcholine systems, [19] they promote the formation of non-lamellar phases in unsaturated phosphatidylethanolamines [20] and disorder the packing of phosphatidylserine bilayers. [21] The ability of triorganotin compounds to transport organic anions such as carboxyfluorescein across phospholipids bilayers by exchange diffusion with chloride has been reported. Accordingly, the anion exchange through erythrocyte membranes was suggested to be related to the hemolytic activity of triorganotin compounds.…”