View source for 1wb3

[[Image:1wb3.gif|left|200px]]<br /><applet load="1wb3" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="1wb3, resolution 3.20&Aring;" />
'''CRYSTAL STRUCTURE OF TRANSLATION ELONGATION FACTOR SELB FROM METHANOCOCCUS MARIPALUDIS IN COMPLEX WITH THE GTP ANALOGUE GPPNHP'''<br />

==Overview==
In all three kingdoms of life, SelB is a specialized translation, elongation factor responsible for the cotranslational incorporation of, selenocysteine into proteins by recoding of a UGA stop codon in the, presence of a downstream mRNA hairpin loop. Here, we present the X-ray, structures of SelB from the archaeon Methanococcus maripaludis in the, apo-, GDP- and GppNHp-bound form and use mutational analysis to, investigate the role of individual amino acids in its aminoacyl-binding, pocket. All three SelB structures reveal an EF-Tu:GTP-like domain, arrangement. Upon binding of the GTP analogue GppNHp, a conformational, change of the Switch 2 region in the GTPase domain leads to the exposure, of SelB residues involved in clamping the 5' phosphate of the tRNA. A, conserved extended loop in domain III of SelB may be responsible for, specific interactions with tRNA(Sec) and act as a ruler for measuring the, extra long acceptor arm. Domain IV of SelB adopts a beta barrel fold and, is flexibly tethered to domain III. The overall domain arrangement of SelB, resembles a 'chalice' observed so far only for initiation factor, IF2/eIF5B. In our model of SelB bound to the ribosome, domain IV points, towards the 3' mRNA entrance cleft ready to interact with the downstream, secondary structure element.

==About this Structure==
1WB3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanococcus_maripaludis Methanococcus maripaludis] with MG, SO4, GNP and DXC as [http://en.wikipedia.org/wiki/ligands ligands]. Known structural/functional Site: <scene name='pdbsite=AC1:Dxc Binding Site For Chain C'>AC1</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1WB3 OCA]. 

==Reference==
Selenocysteine tRNA-specific elongation factor SelB is a structural chimaera of elongation and initiation factors., Leibundgut M, Frick C, Thanbichler M, Bock A, Ban N, EMBO J. 2005 Jan 12;24(1):11-22. Epub 2004 Dec 23. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15616587 15616587]
[[Category: Methanococcus maripaludis]]
[[Category: Single protein]]
[[Category: Ban, N.]]
[[Category: Boeck, A.]]
[[Category: Frick, C.]]
[[Category: Leibundgut, M.]]
[[Category: Thanbichler, M.]]
[[Category: DXC]]
[[Category: GNP]]
[[Category: MG]]
[[Category: SO4]]
[[Category: protein synthesis]]
[[Category: ribosome]]
[[Category: selenium]]
[[Category: selenocysteine]]

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