| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Hebert, Hans, et al.
(författare)
-
Renal, Na,K-ATPase structure from cryo-electron microscopy of two-dimensional crystals.
- 2003
-
Ingår i: Annals of the New York Academy of Sciences. - 0077-8923. ; 986, s. 9-16
-
Tidskriftsartikel (refereegranskat)abstract
- The molecular structure of Na,K-ATPase was determined by electron crystallography from two-dimensional crystals induced in purified membranes isolated from the outer medulla of pig kidney. The P2 type unit cell contains two protomers in the E2 conformation, each of them with a size of 65 x 75 x 150 Å3. The , ß, and subunits in the membrane crystals were demonstrated in the crystals with Western blotting and related to distinct domains in the density map. The subunit corresponds to most of the density in the transmembrane region as well as to the large hydrophilic headpiece on the cytoplasmic side of the membrane. The headpiece is divided into three separated domains. One of these gives rise to an elongated projection onto the membrane plane, while the putative nucleotide binding and phosphorylation domains form compact densities in the rest of the cytoplasmic part of the structure. Density on the extracellular face corresponds to the protein part of the ß subunit. Ten helices from the catalytic a subunit correspond to two groups of distinct densities in the transmembrane region. The structure of the lipid bilayer spanning part also suggests positions for the transmembrane helices from the ß and subunits. The overall structure of the subunit of Na,K-ATPase as determined here by cryo-electron microscopy is similar to the X-ray structure of Ca-ATPase. However, conformational changes between the E1 and E2 forms are suggested by different relative positions of cytoplasmic domains
|
|
| 5. |
|
|
| 6. |
- Koeck, Philip J. B., et al.
(författare)
-
3D-correlation-averaging for membrane-protein-crystals
- 2008
-
Ingår i: EMC 2008 14th European Microscopy Congress. - Berlin, Heidelberg : Springer Berlin Heidelberg. ; , s. 55-56
-
Konferensbidrag (refereegranskat)abstract
- Few 2-dimensional protein crystals can be used to determine high-resolution structures, whereas most electron crystallography projects remain at a resolution around 10 Ångström. This might be partly due to lack of flatness of many two-dimensional crystals [1]. We have investigated this problem and suggest single particle projection matching (3D-correlation averaging) of locally averaged unit cells to improve the quality of three-dimensional maps. Theoretical considerations and tests on simulated data demonstrate the feasibility of this refinement method [2].
|
|
| 7. |
- Koeck, Philip J. B., et al.
(författare)
-
Single particle refinement in electron crystallography : A pilot study
- 2007
-
Ingår i: Journal of Structural Biology. - : Elsevier BV. - 1047-8477 .- 1095-8657. ; 160:3, s. 344-352
-
Tidskriftsartikel (refereegranskat)abstract
- Electron crystallography can be used to determine the structures of membrane proteins at near-atomic resolution in some cases. However, most electron crystallography projects remain at a resolution around 10 Å. This might be partly due to lack of flatness of many two-dimensional crystals. We have investigated this problem and suggest single particle processing of locally averaged unit cells to improve the quality and possibly the resolution of three-dimensional maps. Applying this method to the secondary transporter melibiose permease we have calculated a three-dimensional map that is clearer and easier to interpret than the map derived using purely electron-crystallographic methods.
|
|
| 8. |
|
|
| 9. |
- Lambert, W, et al.
(författare)
-
Subunit arrangement in the dodecameric chloroplast small heat shock protein Hsp21
- 2011
-
Ingår i: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 20:2, s. 291-301
-
Tidskriftsartikel (refereegranskat)abstract
- Unfolding proteins are prevented from irreversible aggregation by small heat shock proteins (sHsps) through interactions that depend on a dynamic equilibrium between sHsp subunits and sHsp oligomers. A chloroplast-localized sHsp, Hsp21, provides protection to client proteins to increase plant stress resistance. Structural information is lacking concerning the oligomeric conformation of this sHsp. We here present a structure model of Arabidopsis thaliana Hsp21, obtained by homology modeling, single-particle electron microscopy, and lysine-specific chemical crosslinking. The model shows that the Hsp21 subunits are arranged in two hexameric discs, similar to a cytosolic plant sHsp homolog that has been structurally determined after crystallization. However, the two hexameric discs of Hsp21 are rotated by 25 degrees in relation to each other, suggesting a role for global dynamics in dodecamer function.
|
|
| 10. |
|
|
