SelB

Elongation factor SelB uses several methods to recognize the selenocysteine insertion sequence found in messenger RNA. The insertion sequence forms a hairpin loop with an unstacked guanine base in the loop. This guanine forms specific hydrogen bonds with the protein and with two bridging water molecules (shown in cyan in the jmol). The planar base is also sandwiched between three amino acids in the protein, which form a tight hydrophobic pocket. This is best seen using a spacefilling diagram. The overall shape of the hairpin is recognized by contacts with several arginine and lysine amino acids. In particular, notice the intimate contact formed by both the charged nitrogen and hydrophobic carbon chain of arginine 606.

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This page complements the article on Selenocysteine Synthase in the Molecule of the Month Series. See also Teaching Scenes, Tutorials, and Educators' Pages.

3D structures of SelB

1lva – MtSelB C terminal – Moorella thermoacetica
2v9v - MtSelB winged-helix domains
4aca – MmSelB – Methanococcus maripaludis

SelB complex with nucleotides

4ac9 – MmSelB + GDP
4acb – MmSelB + GPPNHP
1wsu, 2uwm - MtSelB C terminal + RNA
2pjp – EcSelB mRNA-binding domain + RNA – Eschrichia coli
2ply - EcSelB mRNA-binding domain (mutant) + RNA

Additional Resources

For additional information, see: Translation

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David S. Goodsell, Michal Harel, Eric Martz, David Canner, Joel L. Sussman, Alexander Berchansky, Eran Hodis