Cryo-electron crystallography of small and mosaic 2-D crystals: an assessment of a procedure for high-resolution data retrieval

Stoylova, Svetla; Ford, Robert C.; Holzenburg, Andreas

doi:10.1016/s0304-3991(99)00039-x

Cited by 6 publications

(10 citation statements)

References 30 publications

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“…3B. This supports the conclusion that the higher plant PSII complex is monomeric in vivo , as suggested previously [14,15,19–21,23] . Clearly, caution must be exercised in a more detailed comparison of the two projection maps especially regarding the identification of transmembrane helices, because in the native PSII structure, additional extrinsic proteins and loops will be superimposed (compare to Figure 4), whereas in the current deposition of the cyanobacterial structure, only the transmembrane regions and two of the extrinsic subunits are defined [12] .…”

Section: Resultssupporting

confidence: 91%

“…Such native crystals are inevitably smaller than crystals of isolated proteins [10] or purified complexes of proteins [11]. However it has been shown using experimental data [22] and by simulations [23] that averaging of cryo‐electron microscopy data for several small crystalline areas is practical and results in structural data equivalent in quality to that obtained from much larger single crystalline arrays.…”

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confidence: 99%

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An alternative model for photosystem II/light harvesting complex II in grana membranes based on cryo‐electron microscopy studies

Ford

Stoylova

Holzenburg

2002

European Journal of Biochemistry

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The photosynthetic protein complexes in plants are located in the chloroplast thylakoid membranes. These membranes have an ultrastructure that consists of tightly stacked ÔgranaÕ regions interconnected by unstacked membrane regions. The structure of isolated grana membranes has been studied here by cryo-electron microscopy. The data reveals an unusual arrangement of the photosynthetic protein complexes, staggered over two tightly stacked planes. Chaotrope treatment of the paired grana membranes has allowed the separation and isolation of two biochemically distinct membrane fractions. These data have led us to an alternative model of the ultrastructure of the grana where segregation exists within the grana itself. This arrangement would change the existing view of plant photosynthesis, and suggests potential links between cyanobacterial and plant photosystem II light harvesting systems.

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Section: Resultssupporting

confidence: 91%

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confidence: 99%

An alternative model for photosystem II/light harvesting complex II in grana membranes based on cryo‐electron microscopy studies

Ford

Stoylova

Holzenburg

2002

European Journal of Biochemistry

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“…When observed in the electron microscope, these samples may also infrequently be seen to contain 2D crystals of PSII which, if suitably well ordered, are excellent for the elucidation of PSII structure. These arrays have so far been used for the calculation of 2D projection maps and three‐dimensional (3D) maps of native PSII to various resolution limits up to about 13 Å[2,19–21,25–27]. The viridis‐zb63 mutant of barley ( Hordeum vulgare ), which is used in this study, lacks photosystem I (PSI) but retains a fully intact PSII [28,29].…”

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confidence: 99%

Structural analysis of photosystem II in far‐red‐light‐adapted thylakoid membranes

Stoylova

Flint

Ford

et al. 2000

European Journal of Biochemistry

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We studied two-dimensional crystals of the major pigment±protein complex, photosystem II, in far-red-lightadapted thylakoid membranes of the viridis-zb63 mutant of barley. Significantly larger grana membranes were produced with an increased synthesis of the entire photosystem II complex. These red-light-adapted membranes also contained two-dimensional crystals with a high frequency. Three different crystal forms of photosystem II were observed, providing the following data which further our understanding of the architecture of the native complex. (a) The oligomeric form of photosystem II in the membrane was monomeric in all crystal forms, but with a clear non-crystallographic pseudo-twofold symmetry. This was more apparent on the lumenal face of the complex. (b) The variability of unit cell contacts in different crystal forms implied that the peripheral lightharvesting antenna complex and the core of the complex were loosely connected. These peripheral subunits were predicted to rearrange so that they can either encircle the core complex or associate in parallel channels separated by lines of core complexes. (c) Grana membranes were found to retain a double-layered inside-out character, with a stromal face-to-stromal face packing. However, the presence of a crystal in one membrane did not necessarily impose crystallinity on its pair.

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“…Although the previously published "averaging small and mosaic crystals" methods (Perkins et al, 1995;Stoylova et al, 1999) can retrieve structural data to a resolution higher than an individual crystalline area extends to, it is based more on the EC method and relies on accurate determination of the phase origin and lattice parameters. Our method treats each patch (composed of several unit cells) as a protein particle in the conventional SPR procedure and processes it further.…”

Section: Discussionmentioning

confidence: 99%

A Refined Single-Particle Reconstruction Procedure to Process Two-Dimensional Crystal Images from Transmission Electron Microscopy

et al. 2015

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Single-particle reconstruction (SPR) and electron crystallography (EC), two major applications in electron microscopy, can be used to determine the structure of membrane proteins. The three-dimensional (3D) map is obtained from separated particles in conventional SPR, but from periodic unit cells in EC. Here, we report a refined SPR procedure for processing 2D crystal images. The method is applied to 2D crystals of melibiose permease, a secondary transporter in Escherichia coli. The current procedure is improved from our previously published one in several aspects. The "gold standard Fourier shell correlation" resolution of our final reconstruction reaches 13 Å, which is significantly better than the previously obtained 17 Å resolution. The choices of different refinement parameters for reconstruction are discussed. Our refined SPR procedure could be applied to determine the structure of other membrane proteins in small or locally distorted 2D crystals, which are not ideal for EC.

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Cryo-electron crystallography of small and mosaic 2-D crystals: an assessment of a procedure for high-resolution data retrieval

Cited by 6 publications

References 30 publications

An alternative model for photosystem II/light harvesting complex II in grana membranes based on cryo‐electron microscopy studies

An alternative model for photosystem II/light harvesting complex II in grana membranes based on cryo‐electron microscopy studies

Structural analysis of photosystem II in far‐red‐light‐adapted thylakoid membranes

A Refined Single-Particle Reconstruction Procedure to Process Two-Dimensional Crystal Images from Transmission Electron Microscopy

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