Multi-lamellar organization of fully deuterated lipid extracts of yeast membranes

Abstract

Neutron scattering studies on mimetic biomembranes are currently limited by the low availability of deuterated unsaturated lipid species. In the present work, results from the first neutron diffraction experiments on fully deuterated lipid extracts from the yeast Pichia pastoris are presented. The structural features of these fully deuterated lipid stacks are compared with those of their hydrogenous analogues and with other similar synthetic systems. The influence of temperature and humidity on the samples has been investigated by means of small momentum-transfer neutron diffraction. All of the lipid extracts investigated self-assemble into multi-lamellar stacks having different structural periodicities; the stacking distances are affected by temperature and humidity without altering the basic underlying arrangement. At high relative humidity the deuterated and hydrogenous samples are similar in their multi-lamellar arrangement, being characterized by two main periodicities of ∼75 and ∼110 Å reflecting the presence of a large number of polar phospholipid molecules. Larger differences are found at lower relative humidity, where hydrogenous lipids are characterized by a larger single lamellar structure than that observed in the deuterated samples. In both cases the heterogeneity in composition is reflected in a wide structural complexity. The different behaviour upon dehydration can be related to compositional differences in the molecular composition of the two samples, which is attributed to metabolic effects related to the use of perdeuterated growth media.

Effect of deuteration on the phase behaviour and structure of lamellar phases of phosphatidylcholines – Deuterated lipids as proxies for the physical properties of native bilayers

“…Deuterated lipids have been used to study the effects of chain length [20] and pressure [21] on bilayer properties and on the thermodynamics of monolayers [22], amongst much else. Deuterated lipids have also been used for understanding how other molecules (e.g., solutes, macromolecules, proteins etc) interact with membranes [23][24][25][26][27][28].…”

Structural Insights on Fusion Mechanisms of Extracellular Vesicles with Model Plasma Membrane

“…NR data on EVs with two different solvent contrasts were collected and simultaneously fitted − 3 x 10 -6 Å -2 ). Although higher than the thickness of both synthetic and natural lipid extracts which is generally around 5.5 nm, [34][35][36] the thickness of the EV-based bilayer is compatible with one single bilayer. Further, the scattering profile is consistent with the presence of molecules other than lipids, as large proteins, as part of the deposited membrane.…”

Neutron scattering in the biological sciences: progress and prospects

“…In contrast, the methylotrophic yeast Pichia pastoris (also known as Komagataella pastoris and K. phaffii) has been used to produce highly deuterium-enriched chitosan (Russell et al, 2015), lipids (De Ghellinck et al, 2014;Gerelli et al, 2014;Luchini et al, 2018) and cholesterol (Moulin et al, 2018), and uniform partially deuterium-labeled heterologous eukaryotic proteins (Bodenheimer et al, 2018;Dunne et al, 2017) for neutron scattering studies. Each of the following is likely to have contributed to the choice of P. pastoris for producing deuterium-labeled materials: the high overexpression efficiencies of secreted and membrane-incorporated proteins per unit culture volume (Macauley-Patrick et al, 2005), the low concentration of natively secreted proteins (Cregg et al, 2000;Love et al, 2016) and the ability to use relatively inexpensive D 4 -labeled methanol as a carbon source.…”

“…However, the cost and effort of obtaining tail-deuterated lipids are prohibitive in most cases since most biomimetic membranes contain mixtures of mostly unsaturated lipids that are difficult to synthesize in their deuterated forms. Rather than synthesizing those lipids, some facilities consequently engage in the extraction of lipids from bacteria or yeasts grown in deuterated media (De Gerelli et al, 2014).…”