In vitro analysis of the plastid terminal oxidase in photosynthetic electron transport

The redox state of the photosynthetic electron transport chain acts as a critical sensing mechanism by regulating the transcription of key genes involved in the acclimation response to a change in the environment. In the present study we show that the small LuxR-type regulator PedR interacts with Trx (thioredoxin) to achieve photosynthetic electron-transport-dependent transcriptional regulation in the cyanobacterium Synechocystis sp. PCC 6803. TrxM, an isoform of Trx, was isolated as an interacting factor of PedR by pull-down assays. In vitro analysis revealed that the intermolecular disulfide bond formed between Cys80 residues of the PedR homodimer was reduced by both TrxM and TrxX. It has been shown previously that, although PedR is active under low-light conditions, it becomes transiently inactivated following a shift to high-light conditions, with a concomitant conformational change [Nakamura and Hihara (2006) J. Biol. Chem. 281, 36758–36766]. In the present study, we found that the conformational change of PedR and the change in the transcript level of its target gene were minimal when mutants of Synechocystis that lack ferredoxin–Trx reductase or NADPH–Trx reductase were exposed to high levels of light. These results indicate that the reduction of PedR by Trx causes transient inactivation of PedR upon the shift of cyanobacterial cells to high-light conditions.

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Plastid terminal oxidase requires translocation to the grana stacks to act as a sink for electron transport

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1719070115 ◽

2018 ◽

Vol 115 (38) ◽

pp. 9634-9639 ◽

Cited By ~ 9

Author(s):

Piotr Stepien ◽

Giles N. Johnson

Keyword(s):

Electron Transport ◽

Brassica Species ◽

Photosynthetic Electron Transport ◽

Terminal Oxidase ◽

Significant Activity ◽

Salt Tolerant ◽

Sensitive Species ◽

Tolerant Plants ◽

Eutrema Salsugineum ◽

Plastid Terminal Oxidase

The plastid terminal oxidase (PTOX) has been shown to be an important sink for photosynthetic electron transport in stress-tolerant plants. However, overexpression studies in stress-sensitive species have previously failed to induce significant activity of this protein. Here we show that overexpression of PTOX from the salt-tolerant brassica species Eutrema salsugineum does not, alone, result in activity, but that overexpressing plants show faster induction and a greater final level of PTOX activity once exposed to salt stress. This implies that an additional activation step is required before activity is induced. We show that that activation involves the translocation of the protein from the unstacked stromal lamellae to the thylakoid grana and a protection of the protein from trypsin digestion. This represents an important activation step and opens up possibilities in the search for stress-tolerant crops.

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The native structure of the eukaryotic ribosome

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075890 ◽

1983 ◽

Vol 41 ◽

pp. 432-433

Author(s):

R.A. Milligan ◽

P.N.T. Unwin

Keyword(s):

Ribosomal Proteins ◽

Crystal Form ◽

Native Structure ◽

X Ray Diffraction ◽

Eukaryotic Ribosome ◽

Vitro Analysis ◽

In Vitro Analysis ◽

Resolution Structure ◽

Stable Unit

A detailed understanding of the mechanism of protein synthesis will ultimately depend on knowledge of the native structure of the ribosome. Towards this end we have investigated the low resolution structure of the eukaryotic ribosome embedded in frozen buffer, making use of a system in which the ribosomes crystallize naturally.The ribosomes in the cells of early chicken embryos form crystalline arrays when the embryos are cooled at 4°C. We have developed methods to isolate the stable unit of these arrays, the ribosome tetramer, and have determined conditions for the growth of two-dimensional crystals in vitro, Analysis of the proteins in the crystals by 2-D gel electrophoresis demonstrates the presence of all ribosomal proteins normally found in polysomes. There are in addition, four proteins which may facilitate crystallization. The crystals are built from two oppositely facing P4 layers and the predominant crystal form, accounting for >80% of the crystals, has the tetragonal space group P4212, X-ray diffraction of crystal pellets demonstrates that crystalline order extends to ~ 60Å.

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1163: Radial Dilation of Ureteral Balloons: A Comparative in-Vitro Analysis

The Journal of Urology ◽

10.1016/s0022-5347(18)35308-4 ◽

2005 ◽

Vol 173 (4S) ◽

pp. 315-316

Author(s):

Kari Hendlin ◽

Brynn Lund ◽

Manoj Monga

Keyword(s):

Vitro Analysis ◽

In Vitro Analysis

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An In Vitro Analysis of Ligament Reconstruction or Extension Osteotomy on Trapeziometacarpal Joint Stability and Contact Area

Yearbook of Hand and Upper Limb Surgery ◽

10.1016/s1551-7977(08)70357-1 ◽

2007 ◽

Vol 2007 ◽

pp. 214-215 ◽

Cited By ~ 1

Author(s):

B. Wilhelmi

Keyword(s):

Contact Area ◽

Ligament Reconstruction ◽

Joint Stability ◽

Trapeziometacarpal Joint ◽

Vitro Analysis ◽

In Vitro Analysis

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Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614605 ◽

1999 ◽

Vol 81 (06) ◽

pp. 951-956 ◽

Cited By ~ 59

Author(s):

J. Corral ◽

R. González-Conejero ◽

J. Rivera ◽

F. Ortuño ◽

P. Aparicio ◽

...

Keyword(s):

Venous Thrombosis ◽

Cell Types ◽

Receptor Expression ◽

Case Control Studies ◽

Platelet Surface ◽

Vitro Analysis ◽

And Function ◽

In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

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