This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2aev
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:2aev.gif|left|200px]] | [[Image:2aev.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_2aev", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_2aev| PDB=2aev | SCENE= }} | |
| - | | | + | |
| - | + | ||
| - | }} | + | |
'''MJ0158, NaBH4-reduced form''' | '''MJ0158, NaBH4-reduced form''' | ||
| Line 31: | Line 28: | ||
[[Category: Rother, M.]] | [[Category: Rother, M.]] | ||
[[Category: Wahl, M C.]] | [[Category: Wahl, M C.]] | ||
| - | [[Category: | + | [[Category: Homo-oligomerization]] |
| - | [[Category: | + | [[Category: Plp]] |
| - | [[Category: | + | [[Category: Pyridoxal phosphate]] |
| - | [[Category: | + | [[Category: Selenocysteine synthase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 18:57:42 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 15:57, 3 May 2008
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. 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 Page seeded by OCA on Sat May 3 18:57:42 2008
