Steps for Constructing Synthetic Membrane Curvature-Inducing DNA Origami Scaffolds

Abstract

Biological membranes are dynamic cellular barriers that suffer deformation and bending. Despite huge effort in identifying the physical-chemical fundaments of membrane curvature, the particular mechanisms and elements of curvature induction on which cells actually base their membrane transformations are still poorly understood. In this project, we aim to fill this gap by engineering a minimal membrane curvature-inducing scaffold.Due to its exclusive nano-engineering properties, the DNA origami technology was chosen to build synthetic curvature-inducing scaffolds. This state-of-the-art technology enables the folding of long strands of DNA into nano-objects with defined shapes by using sequence-specific short DNA staples. Here, we designed DNA nanostructures with defined curvature and shape, as well as specific membrane binding positions. Hybrid origami scaffolds with specific functional membrane-attachment groups have been produced and the interaction of those hybrid scaffolds with lipid membrane model systems was studied, more precisely in terms of localization, membrane density and induction of membrane curvature.By using fluorescence microscopy, we show that the positioning and number of the membrane binding elements are essential to ensure an effective localization of the DNA nanostructures to the membrane. Moreover, the requirements seem to be dependent on the intrinsic curvature of the nanostructures. Interestingly, the quantitative characterization of our minimal membrane-scaffolds through fluorescence correlation spectroscopy (FCS) unravels that they may bind cooperatively to the membrane. In the end, our approach aims to reveal the minimal set of modules needed for shape-dependent induction of membrane curvature.In this work, we have developed and characterized the membrane binding properties of a synthetic membrane scaffold, which can act as biomimetic of the properties of biological scaffolding elements.