Protein-lipid charge interactions

Table 6 shows that the surface of polycarbonate with adsorbed serum albumin is the most suitable one to be used in implant devices. The behavior of all lipids toward blood-polymer interaction is not similar and may change depending on the nature of lipid, net charge of the lipid-adsorbed surface and the lipid-protein/ lipid-platelet interaction at the interface. Under conditions of high cholesterol concentrations addition of vitamin C leads to suitable surface characteristics of polycarbonate. The question is how to garantee the preferential the albumin adsorption on an implant surface In works of Malmsten and Lassen [123] competitive adsorption at hydrophobic surfaces from binary protein solutions was... 

In this case, highly specific biochemical interactions provide the means of separation. The stationary phase contains specific groups of molecules which can only adsorb the sample if certain steric and charge-related conditions are satisfied (cf. interaction between antigens and antibodies). Affinity chromatography can be used to isolate proteins (enzymes as well as stmctural proteins), lipids, etc., from complex mixtures without involving any great expenditure. 

The mechanism of RTA unfolding in the ER is unknown, but could involve target cell proteins, lipid membranes, or both. Interaction with negatively charged Hpids was shown in vitro to induce significant structural changes in RTA, leading to speculation that the ER membrane may play a role... 

Lipids are not covalently bound in membranes but rather interact dynamically to form transient arrangements with asymmetry both perpendicular and parallel to the plane of the lipid bilayer. The fluidity, supermolecular-phase propensity, lateral pressure and surface charge of the bilayer matrix is largely determined by the collective properties of the complex mixture of individual lipid species, some of which are shown in Fig. 8.1. Lipids also interact with and bind to proteins in stiochiometric amounts affecting protein structure and function. The broad range of lipid properties coupled with the dynamic organization of lipids in membranes multiplies their functional diversity in modulating the environment and therefore the function of membrane proteins. 

Ion-mobility spectrometry (IMS) separates ions based on their size/charge ratios and their interactions with a buffer gas [44], The shape of ions also has an effect on the separation [45]. Following ionization, the ions are introduced into a chamber filled with a neutral gas at controlled pressure [45], The separation proceeds in the presence of a relatively weak field. While IMS alone has great importance in national security applications (e.g., detection of explosives), if coupled with MS - it supports analyses of biomolecular species (proteins, lipid isomers) which cannot be fully resolved by MS alone. Both IMS and MS handle gas-phase ions, which makes them particularly compatible with each other. In IMS, the velocity of the ions is proportional to the electric field with the proportionality factor (K) [44,46] ... 

Li LB, Vorobyov I, Allen TW (2012) The role of membrane thickness in charged protein-lipid interactions. Biochim Biophys Acta 1818(2) 135-145... 

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