Membrane Binding Promotes Annexin A2 Oligomerization.

Annexin A2 (AnxA2) is a cytosolic Ca regulated membrane binding protein that can induce lipid domain formation and plays a role in exocytosis and endocytosis. To better understand the mode of annexin-membrane interaction, we analyzed membrane-bound AnxA2 assemblies by employing a novel 3-armed chemical crosslinker and specific AnxA2 mutant proteins. Our data show that AnxA2 forms crosslinkable oligomers upon binding to membranes containing negatively charged phospholipids.

Controlling Complex Stability in Photoresponsive Macromolecular Host-Guest Systems: Toward Reversible Capture of DNA by Cyclodextrin Vesicles.

An effective and universal method for delivering structurally diverse biomolecules in vivo would greatly benefit modern drug therapy, but has yet to be discovered. Self-assembled supramolecular complexes containing vesicles of amphiphilic cyclodextrin and linker molecules with an azobenzene guest unit and a charged functionality have been established as nanoscale carriers for proteins and DNA, making use of multivalent electrostatic attraction. However, light-induced cargo release is only feasible up to a maximum net charge of the biomacromolecules.

Dynamic glycosylation of liposomes by thioester exchange.

The interplay of dynamic functionalization and specific molecular recognition on biological membranes is key to numerous physiological processes. In this work we present a simple glycocalyx model based on the covalent yet reversible glycosylation of liposomes and subsequent recognition by a lectin. Reversible thioester exchange of membrane embedded amphiphilic thioesters with thiol-tagged d-mannose in solution is performed at physiologically relevant conditions.

Preparation of Functional Alternating Polymer Brushes and Their Orthogonal Surface Modification through Microcontact Printing.

This paper reports microcontact printing (μCP) to immobilize an alkoxyamine initiator (regulator) on glass and silicon substrates and subsequent surface-initiated alternating nitroxide-mediated copolymerization (siNMP) of hexafluoroisopropyl acrylate (HFIPA) and 7-octenylvinyl ether (OVE). The resulting patterned polymer brushes are analyzed by using atomic force microscopy (AFM). In addition, site-specific post-functionalization of the alternating polymer brushes by applying two orthogonal surface reactions is achieved with thiols and amines through μCP.

Light-triggered capture and release of DNA and proteins by host-guest binding and electrostatic interaction.

The development of an effective and general delivery method that can be applied to a large variety of structurally diverse biomolecules remains a bottleneck in modern drug therapy. Herein, we present a supramolecular system for the dynamic trapping and light-stimulated release of both DNA and proteins. Self-assembled ternary complexes act as nanoscale carriers, comprising vesicles of amphiphilic cyclodextrin, the target biomolecules and linker molecules with an azobenzene unit and a charged functionality.