1n9w
From Proteopedia
(New page: 200px<br /><applet load="1n9w" size="450" color="white" frame="true" align="right" spinBox="true" caption="1n9w, resolution 2.3Å" /> '''Crystal structure of ...) |
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| - | [[Image:1n9w.jpg|left|200px]]<br /><applet load="1n9w" size=" | + | [[Image:1n9w.jpg|left|200px]]<br /><applet load="1n9w" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1n9w, resolution 2.3Å" /> | caption="1n9w, resolution 2.3Å" /> | ||
'''Crystal structure of the non-discriminating and archaeal-type aspartyl-tRNA synthetase from Thermus thermophilus'''<br /> | '''Crystal structure of the non-discriminating and archaeal-type aspartyl-tRNA synthetase from Thermus thermophilus'''<br /> | ||
==Overview== | ==Overview== | ||
| - | In most organisms, tRNA aminoacylation is ensured by 20 aminoacyl-tRNA | + | In most organisms, tRNA aminoacylation is ensured by 20 aminoacyl-tRNA synthetases (aaRSs). In eubacteria, however, synthetases can be duplicated as in Thermus thermophilus, which contains two distinct AspRSs. While AspRS-1 is specific, AspRS-2 is non-discriminating and aspartylates tRNA(Asp) and tRNA(Asn). The structure at 2.3 A resolution of AspRS-2, the first of a non-discriminating synthetase, was solved. It differs from that of AspRS-1 but has resemblance to that of discriminating and archaeal AspRS from Pyrococcus kodakaraensis. The protein presents non-conventional features in its OB-fold anticodon-binding domain, namely the absence of a helix inserted between two beta-strands of this fold and a peculiar L1 loop differing from the large loops known to interact with tRNA(Asp) identity determinant C36 in conventional AspRSs. In AspRS-2, this loop is small and structurally homologous to that in AsnRSs, including conservation of a proline. In discriminating Pyrococcus AspRS, the L1 loop, although small, lacks this proline and is not superimposable with that of AspRS-2 or AsnRS. Its particular status is demonstrated by a loop-exchange experiment that renders the Pyrococcus AspRS non-discriminating. |
==About this Structure== | ==About this Structure== | ||
| - | 1N9W is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http:// | + | 1N9W is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N9W OCA]. |
==Reference== | ==Reference== | ||
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[[Category: biosynthetic protein]] | [[Category: biosynthetic protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:03:48 2008'' |
Revision as of 12:03, 21 February 2008
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Crystal structure of the non-discriminating and archaeal-type aspartyl-tRNA synthetase from Thermus thermophilus
Overview
In most organisms, tRNA aminoacylation is ensured by 20 aminoacyl-tRNA synthetases (aaRSs). In eubacteria, however, synthetases can be duplicated as in Thermus thermophilus, which contains two distinct AspRSs. While AspRS-1 is specific, AspRS-2 is non-discriminating and aspartylates tRNA(Asp) and tRNA(Asn). The structure at 2.3 A resolution of AspRS-2, the first of a non-discriminating synthetase, was solved. It differs from that of AspRS-1 but has resemblance to that of discriminating and archaeal AspRS from Pyrococcus kodakaraensis. The protein presents non-conventional features in its OB-fold anticodon-binding domain, namely the absence of a helix inserted between two beta-strands of this fold and a peculiar L1 loop differing from the large loops known to interact with tRNA(Asp) identity determinant C36 in conventional AspRSs. In AspRS-2, this loop is small and structurally homologous to that in AsnRSs, including conservation of a proline. In discriminating Pyrococcus AspRS, the L1 loop, although small, lacks this proline and is not superimposable with that of AspRS-2 or AsnRS. Its particular status is demonstrated by a loop-exchange experiment that renders the Pyrococcus AspRS non-discriminating.
About this Structure
1N9W is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Non-discriminating and discriminating aspartyl-tRNA synthetases differ in the anticodon-binding domain., Charron C, Roy H, Blaise M, Giege R, Kern D, EMBO J. 2003 Apr 1;22(7):1632-43. PMID:12660169
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