Membrane proteins play a tremendously important role in cell physiology and serve as a target for an increasing number of drugs. Structural information is key to understanding their function and for developing new strategies for combating disease. However, the complex physical chemistry associated with membrane proteins has made them more difficult to study than their soluble cousins. Electron ...

The nicotinic acetylcholine receptor (AChR) was expressed in Xenopus oocytes from in vitro transcribed mRNA and was imaged by atomic force microscopy. A characteristic pentameric structure of AChR was readily observed on the extracellular face of the cell membrane, with a central pore surrounded by protruding AChR subunits. These structures were seen only in mRNA-injected oocytes that also gave...

Membranes are often damaged by freezing and/or dehydration, and this damage may be reduced by solutes. In many cases, these phenomena can be explained by the physical behavior of membrane-solute-water systems. Both solutes and membranes reduce the freezing temperature of water, although their effects are not simply additive. The dehydration of membranes induces large mechanical stresses in the ...

Microporous poly(vinylidene fluoride) (PVDF) membranes were prepared from PVDF/N,N-dimethylacetamide (DMAC) solutions by using upercritical CO2 phase inversion process. As revealed by scanning electron microscope (SEM) and differential scanning calorimeter (DSC), he PVDF membranes exhibit morphological characteristics resulting from both liquid–liquid phase separation and crystallization, i.e.,...

The structural knowledge of some biological macromolecules helps to understand their mechanisms of working and their role on health sciences, food science and even their effect on the economy. In this work, some recent solutions to crystallogenesis for structural analysis (convective transport, counter-diffusion, the challenge of membrane protein crystallization, and high throughput techniques)...

7.1 The Structure and Role of Biomembranes 7.2 Investigation of Biological Membranes by SFM 7.3 Na,K-ATPase 7.3.1 Structure 7.3.2 Isolation 7.3.3 Crystallization 7.4 Sample Preparation for SFM 7.4.1 Binding of Membrane Fragments onto Mica Surface 7.4.2 Removal of Surface Contaminations 7.4.3 Manipulation of Surface Properties 7.4.4 Water Cell 7.5 Imaging Techniques 7.5.1 Tip-Sample Interactions...

P0, the major protein of peripheral nerve myelin, mediates membrane adhesion in the spiral wraps of the myelin sheath. We have determined the crystal structure of the extracellular domain from P0 (P0ex) at 1.9 A resolution. P0ex is folded like a typical immunoglobulin variable-like domain; five residues at the C-terminus are disordered, suggesting a flexible linkage to the membrane. The require...

A microfluidic device capable of exploiting the permeability of small molecules through polydimethylsiloxane (PDMS) has been fabricated in order to control the contents of microdroplets stored in storage wells. We demonstrate that protein precipitation and crystallization can be triggered by delivery of ethanol from a reservoir channel, thus controlling the protein solubility in microdroplets. ...

With the aim of better understanding the phase behavior of alkyl maltosides (n-alkyl-β-d-maltosides, CnG2) under the conditions of membrane protein crystallization, we studied the influence of poly(ethylene glycol) (PEG) 2000, a commonly used precipitating agent, on the critical micelle concentration (CMC) of the alkyl maltosides by systematic variation of the number n of carbon atoms in the al...

It has been shown experimentally by many researchers that cooling rate and crystallization temperature affect the rate of crystal formation. In this study, crystallization kinetics of coconut oil was measured by monitoring the solid fraction of the oil using pulsed Nuclear Magnetic Resonance (pNMR). Four levels of cooling rate and crytallization temperature were studied. Parameters of crystalli...