2aev
From Proteopedia
(New page: 200px<br /><applet load="2aev" size="450" color="white" frame="true" align="right" spinBox="true" caption="2aev, resolution 2.00Å" /> '''MJ0158, NaBH4-reduce...) |
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| - | [[Image:2aev.gif|left|200px]]<br /><applet load="2aev" size=" | + | [[Image:2aev.gif|left|200px]]<br /><applet load="2aev" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2aev, resolution 2.00Å" /> | caption="2aev, resolution 2.00Å" /> | ||
'''MJ0158, NaBH4-reduced form'''<br /> | '''MJ0158, NaBH4-reduced form'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Bacterial selenocysteine synthase converts seryl-tRNA(Sec) to | + | Bacterial selenocysteine synthase converts seryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec) for selenoprotein biosynthesis. The identity of this enzyme in archaea and eukaryotes is unknown. On the basis of sequence similarity, a conserved open reading frame has been annotated as a selenocysteine synthase gene in archaeal genomes. We have determined the crystal structure of the corresponding protein from Methanococcus jannaschii, MJ0158. The protein was found to be dimeric with a distinctive domain arrangement and an exposed active site, built from residues of the large domain of one protomer alone. The shape of the dimer is reminiscent of a substructure of the decameric Escherichia coli selenocysteine synthase seen in electron microscopic projections. However, biochemical analyses demonstrated that MJ0158 lacked affinity for E. coli seryl-tRNA(Sec) or M. jannaschii seryl-tRNA(Sec), and neither substrate was directly converted to selenocysteinyl-tRNA(Sec) by MJ0158 when supplied with selenophosphate. We then tested a hypothetical M. jannaschii O-phosphoseryl-tRNA(Sec) kinase and demonstrated that the enzyme converts seryl-tRNA(Sec) to O-phosphoseryl-tRNA(Sec) that could constitute an activated intermediate for selenocysteinyl-tRNA(Sec) production. MJ0158 also failed to convert O-phosphoseryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec). In contrast, both archaeal and bacterial seryl-tRNA synthetases were able to charge both archaeal and bacterial tRNA(Sec) with serine, and E. coli selenocysteine synthase converted both types of seryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec). These findings demonstrate that a number of factors from the selenoprotein biosynthesis machineries are cross-reactive between the bacterial and the archaeal systems but that MJ0158 either does not encode a selenocysteine synthase or requires additional factors for activity. |
==About this Structure== | ==About this Structure== | ||
| - | 2AEV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 2AEV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AEV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Engelhardt, H.]] | [[Category: Engelhardt, H.]] | ||
[[Category: Gromadski, K.]] | [[Category: Gromadski, K.]] | ||
| - | [[Category: Kaiser, J | + | [[Category: Kaiser, J T.]] |
| - | [[Category: Rodnina, M | + | [[Category: Rodnina, M V.]] |
[[Category: Rother, M.]] | [[Category: Rother, M.]] | ||
| - | [[Category: Wahl, M | + | [[Category: Wahl, M C.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: homo-oligomerization]] | [[Category: homo-oligomerization]] | ||
| Line 25: | Line 25: | ||
[[Category: selenocysteine synthase]] | [[Category: selenocysteine synthase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:26:43 2008'' |
Revision as of 14:26, 21 February 2008
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MJ0158, NaBH4-reduced form
Overview
Bacterial selenocysteine synthase converts seryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec) for selenoprotein biosynthesis. The identity of this enzyme in archaea and eukaryotes is unknown. On the basis of sequence similarity, a conserved open reading frame has been annotated as a selenocysteine synthase gene in archaeal genomes. We have determined the crystal structure of the corresponding protein from Methanococcus jannaschii, MJ0158. The protein was found to be dimeric with a distinctive domain arrangement and an exposed active site, built from residues of the large domain of one protomer alone. The shape of the dimer is reminiscent of a substructure of the decameric Escherichia coli selenocysteine synthase seen in electron microscopic projections. However, biochemical analyses demonstrated that MJ0158 lacked affinity for E. coli seryl-tRNA(Sec) or M. jannaschii seryl-tRNA(Sec), and neither substrate was directly converted to selenocysteinyl-tRNA(Sec) by MJ0158 when supplied with selenophosphate. We then tested a hypothetical M. jannaschii O-phosphoseryl-tRNA(Sec) kinase and demonstrated that the enzyme converts seryl-tRNA(Sec) to O-phosphoseryl-tRNA(Sec) that could constitute an activated intermediate for selenocysteinyl-tRNA(Sec) production. MJ0158 also failed to convert O-phosphoseryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec). In contrast, both archaeal and bacterial seryl-tRNA synthetases were able to charge both archaeal and bacterial tRNA(Sec) with serine, and E. coli selenocysteine synthase converted both types of seryl-tRNA(Sec) to selenocysteinyl-tRNA(Sec). These findings demonstrate that a number of factors from the selenoprotein biosynthesis machineries are cross-reactive between the bacterial and the archaeal systems but that MJ0158 either does not encode a selenocysteine synthase or requires additional factors for activity.
About this Structure
2AEV is a Single protein structure of sequence from Methanocaldococcus jannaschii with as ligand. Full crystallographic information is available from OCA.
Reference
Structural and functional investigation of a putative archaeal selenocysteine synthase., Kaiser JT, Gromadski K, Rother M, Engelhardt H, Rodnina MV, Wahl MC, Biochemistry. 2005 Oct 11;44(40):13315-27. PMID:16201757
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