Approaches to the High Resolution Structure of Periodic Membrane Proteins

1980 ◽  
Vol 38 ◽  
pp. 666-669
Author(s):  
J.W. Wiggins
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Aqueous Media ◽  
Integral Membrane Proteins ◽  
X Ray Diffraction ◽  
Sequence Determination ◽  
X Ray ◽  
High Resolution Structure ◽  
Gain Access ◽  
Resolution Structure

Integral membrane proteins are particularly difficult to study at high resolution for several reasons. Amino acid sequence determination may be difficult because the fragmentation reagents cannot gain access to the required site, fragments are insoluble in aqueous media, or lipids are difficult to remove. X-ray diffraction studies cannot be undertaken without large enough crystals. Electron microscopy studies of the usual sort cannot be used because dehydration, negative staining, embedding, and other typical procedures are incompatible with the preservation and contrasting of the structure. Even determinations of molecular weight are made difficult by the presence of bound lipid and polysaccharide.

scholarly journals High-resolution structure of the photosynthetic Mn 4 Ca catalyst from X-ray spectroscopy

2007 ◽  
Vol 363 (1494) ◽  
pp. 1139-1147 ◽  
Author(s):  
Junko Yano ◽  
Jan Kern ◽  
Yulia Pushkar ◽  
Kenneth Sauer ◽  
Pieter Glatzel ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Resolution Structure ◽  
Resonant Raman ◽  
X Ray Absorption ◽  
Water Oxidizing Complex ◽  
S States ◽  
Resolution Structure

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn 4 Ca cluster, is described. Issues of X-ray damage, especially at the metal sites in the Mn 4 Ca cluster, are discussed. The structure of the Mn 4 Ca catalyst at high resolution, which has so far eluded attempts of determination by X-ray diffraction, X-ray absorption fine structure (EXAFS) and other spectroscopic techniques, has been addressed using polarized EXAFS techniques applied to oriented photosystem II (PSII) membrane preparations and PSII single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS, is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and Kβ emission) have been used earlier to determine the oxidation states of the Mn 4 Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn 4 Ca cluster as it cycles through the intermediate S-states.

scholarly journals Tricks of the trade used to accelerate high-resolution structure determination of membrane proteins

FEBS Letters ◽  
2010 ◽  
Vol 584 (12) ◽  
pp. 2539-2547 ◽  
Author(s):  
Yo Sonoda ◽  
Alex Cameron ◽  
Simon Newstead ◽  
Hiroshi Omote ◽  
Yoshinori Moriyama ◽  
...  
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Structure Determination ◽  
High Resolution Structure ◽  
Resolution Structure

Study of Diffuse Scattering by Means of High Resolution Structure Images

1976 ◽  
Vol 34 ◽  
pp. 476-477
Author(s):  
Sumio Iijima ◽  
G. R. Anstis
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Diffuse Scattering ◽  
Reciprocal Space ◽  
The Other ◽  
X Ray ◽  
Actual Model ◽  
High Resolution Structure ◽  
Made In ◽  
Resolution Structure

Disorders in crystals with relatively simple structures which gave diffuse scattering have been extensively studied by X-ray or neutron diffraction methods. All these investigations were based on traditional diffraction methods and observations were made in reciprocal space (note observable diffraction intensities can be considered only in terms of interatomic vectors) and therefore the results obtained there leaves considerable ambiguity, particularly when we try to derive an actual model of the disordered crystals. A solution of this problem will be given only by knowing all atom positions in an assembly of atoms and for this case the observable diffracted intensity is given bywhere (xi,yi) and (xj,yj) represent position vectors of the i th and j th atoms with scattering factors fi and fj from an arbitrary origin. On the other hand, a crystal containing imperfections can be defined by

scholarly journals Detergent-free systems for structural studies of membrane proteins

2021 ◽  
Author(s):  
Youzhong Guo
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Cell Membrane ◽  
Membrane Protein ◽  
Structural Biology ◽  
Membrane Lipids ◽  
Native Cell ◽  
Lipid Particles ◽  
High Resolution Structure ◽  
Resolution Structure

Membrane proteins play vital roles in living organisms, serving as targets for most currently prescribed drugs. Membrane protein structural biology aims to provide accurate structural information to understand their mechanisms of action. The advance of membrane protein structural biology has primarily relied on detergent-based methods over the past several decades. However, detergent-based approaches have significant drawbacks because detergents often damage the native protein–lipid interactions, which are often crucial for maintaining the natural structure and function of membrane proteins. Detergent-free methods recently have emerged as alternatives with a great promise, e.g. for high-resolution structure determinations of membrane proteins in their native cell membrane lipid environments. This minireview critically examines the current status of detergent-free methods by a comparative analysis of five groups of membrane protein structures determined using detergent-free and detergent-based methods. This analysis reveals that current detergent-free systems, such as the styrene-maleic acid lipid particles (SMALP), the diisobutyl maleic acid lipid particles (DIBMALP), and the cycloalkane-modified amphiphile polymer (CyclAPol) technologies are not better than detergent-based approaches in terms of maintenance of native cell membrane lipids on the transmembrane domain and high-resolution structure determination. However, another detergent-free technology, the native cell membrane nanoparticles (NCMN) system, demonstrated improved maintenance of native cell membrane lipids with the studied membrane proteins, and produced particles that were suitable for high-resolution structural analysis. The ongoing development of new membrane-active polymers and their optimization will facilitate the maturation of these new detergent-free systems.

Sign in / Sign up

Export Citation Format

Share Document