4md2: Difference between revisions

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== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
BACKGROUND: Radiation therapy treatment of breast cancer, Hodgkin's disease or childhood cancers expose the heart to high local radiation doses, causing an increased risk of cardiovascular disease in the survivors decades after the treatment. The mechanisms that underlie the radiation damage remain poorly understood so far. Previous data show that impairment of mitochondrial oxidative metabolism is directly linked to the development of cardiovascular disease. METHODOLOGY/PRINCIPAL FINDINGS: In this study, the radiation-induced in vivo effects on cardiac mitochondrial proteome and function were investigated. C57BL/6N mice were exposed to local irradiation of the heart with doses of 0.2 Gy or 2 Gy (X-ray, 200 kV) at the age of eight weeks, the control mice were sham-irradiated. After four weeks the cardiac mitochondria were isolated and tested for proteomic and functional alterations. Two complementary proteomics approaches using both peptide and protein quantification strategies showed radiation-induced deregulation of 25 proteins in total. Three main biological categories were affected: the oxidative phophorylation, the pyruvate metabolism, and the cytoskeletal structure. The mitochondria exposed to high-dose irradiation showed functional impairment reflected as partial deactivation of Complex I (32%) and Complex III (11%), decreased succinate-driven respiratory capacity (13%), increased level of reactive oxygen species and enhanced oxidation of mitochondrial proteins. The changes in the pyruvate metabolism and structural proteins were seen with both low and high radiation doses. CONCLUSION/SIGNIFICANCE: This is the first study showing the biological alterations in the murine heart mitochondria several weeks after the exposure to low- and high-dose of ionizing radiation. Our results show that doses, equivalent to a single dose in radiotherapy, cause long-lasting changes in mitochondrial oxidative metabolism and mitochondria-associated cytoskeleton. This prompts us to propose that these first pathological changes lead to an increased risk of cardiovascular disease after radiation exposure.
X-ray-radiation-induced alterations to protein structures are still a severe problem in macromolecular crystallography. One way to avoid the influence of radiation damage is to reduce the X-ray dose absorbed by the crystal during data collection. However, here it is demonstrated using the example of the membrane protein bacteriorhodopsin (bR) that even a low dose of less than 0.06 MGy may induce structural alterations in proteins. This dose is about 500 times smaller than the experimental dose limit which should ideally not be exceeded per data set (i.e. 30 MGy) and 20 times smaller than previously detected specific radiation damage at the bR active site. To date, it is the lowest dose at which radiation modification of a protein structure has been described. Complementary use was made of high-resolution X-ray crystallography and online microspectrophotometry to quantitatively study low-dose X-ray-induced changes. It is shown that structural changes of the protein correlate with the spectroscopically observed formation of the so-called bR orange species. Evidence is provided for structural modifications taking place at the protein active site that should be taken into account in crystallographic studies which aim to elucidate the molecular mechanisms of bR function.


Radiation-induced signaling results in mitochondrial impairment in mouse heart at 4 weeks after exposure to X-rays.,Barjaktarovic Z, Schmaltz D, Shyla A, Azimzadeh O, Schulz S, Haagen J, Dorr W, Sarioglu H, Schafer A, Atkinson MJ, Zischka H, Tapio S PLoS One. 2011;6(12):e27811. doi: 10.1371/journal.pone.0027811. Epub 2011 Dec 8. PMID:22174747<ref>PMID:22174747</ref>
Low-dose X-ray radiation induces structural alterations in proteins.,Borshchevskiy V, Round E, Erofeev I, Weik M, Ishchenko A, Gushchin I, Mishin A, Willbold D, Buldt G, Gordeliy V Acta Crystallogr D Biol Crystallogr. 2014 Oct;70(Pt 10):2675-85. doi:, 10.1107/S1399004714017295. Epub 2014 Sep 27. PMID:25286851<ref>PMID:25286851</ref>


From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

Revision as of 18:53, 29 January 2020

Ground state of bacteriorhodopsin from Halobacterium salinarumGround state of bacteriorhodopsin from Halobacterium salinarum

Structural highlights

4md2 is a 1 chain structure with sequence from Halobacterium sp. nrc-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[BACR_HALSA] Light-driven proton pump.

Publication Abstract from PubMed

X-ray-radiation-induced alterations to protein structures are still a severe problem in macromolecular crystallography. One way to avoid the influence of radiation damage is to reduce the X-ray dose absorbed by the crystal during data collection. However, here it is demonstrated using the example of the membrane protein bacteriorhodopsin (bR) that even a low dose of less than 0.06 MGy may induce structural alterations in proteins. This dose is about 500 times smaller than the experimental dose limit which should ideally not be exceeded per data set (i.e. 30 MGy) and 20 times smaller than previously detected specific radiation damage at the bR active site. To date, it is the lowest dose at which radiation modification of a protein structure has been described. Complementary use was made of high-resolution X-ray crystallography and online microspectrophotometry to quantitatively study low-dose X-ray-induced changes. It is shown that structural changes of the protein correlate with the spectroscopically observed formation of the so-called bR orange species. Evidence is provided for structural modifications taking place at the protein active site that should be taken into account in crystallographic studies which aim to elucidate the molecular mechanisms of bR function.

Low-dose X-ray radiation induces structural alterations in proteins.,Borshchevskiy V, Round E, Erofeev I, Weik M, Ishchenko A, Gushchin I, Mishin A, Willbold D, Buldt G, Gordeliy V Acta Crystallogr D Biol Crystallogr. 2014 Oct;70(Pt 10):2675-85. doi:, 10.1107/S1399004714017295. Epub 2014 Sep 27. PMID:25286851[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Borshchevskiy V, Round E, Erofeev I, Weik M, Ishchenko A, Gushchin I, Mishin A, Willbold D, Buldt G, Gordeliy V. Low-dose X-ray radiation induces structural alterations in proteins. Acta Crystallogr D Biol Crystallogr. 2014 Oct;70(Pt 10):2675-85. doi:, 10.1107/S1399004714017295. Epub 2014 Sep 27. PMID:25286851 doi:http://dx.doi.org/10.1107/S1399004714017295

4md2, resolution 1.73Å

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OCA