View source for 1riq

[[Image:1riq.gif|left|200px]]<br /><applet load="1riq" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1riq, resolution 2.14&Aring;" />
'''The crystal structure of the catalytic fragment of the alanyl-tRNA synthetase'''<br />

==Overview==
Early work on aminoacylation of alanine-specific tRNA (tRNA(Ala)) by alanyl-tRNA synthetase (AlaRS) gave rise to the concept of an early "second genetic code" imbedded in the acceptor stems of tRNAs. A single conserved and position-specific G:U base pair in the tRNA acceptor stem is the key identity determinant. Further understanding has been limited due to lack of a crystal structure of the enzyme. We determined a 2.14 A crystal structure of the 453 amino acid catalytic fragment of Aquifex aeolicus AlaRS. It contains the catalytic domain characteristic of class II synthetases, a helical domain with a hairpin motif critical for acceptor-stem recognition, and a C-terminal domain of a mixed alpha/beta fold. Docking of tRNA(Ala) on AlaRS shows critical contacts with the three domains, consistent with previous mutagenesis and functional data. It also suggests conformational flexibility within the C domain, which might allow for the positional variation of the key G:U base pair seen in some tRNA(Ala)s.

==About this Structure==
1RIQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aquifex_aeolicus Aquifex aeolicus]. Active as [http://en.wikipedia.org/wiki/Alanine--tRNA_ligase Alanine--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.7 6.1.1.7] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RIQ OCA]. 

==Reference==
Alanyl-tRNA synthetase crystal structure and design for acceptor-stem recognition., Swairjo MA, Otero FJ, Yang XL, Lovato MA, Skene RJ, McRee DE, Ribas de Pouplana L, Schimmel P, Mol Cell. 2004 Mar 26;13(6):829-41. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15053876 15053876]
[[Category: Alanine--tRNA ligase]]
[[Category: Aquifex aeolicus]]
[[Category: Single protein]]
[[Category: Lovato, M A.]]
[[Category: McRee, D E.]]
[[Category: Otero, F J.]]
[[Category: Pouplana, L Ribas de.]]
[[Category: Schimmel, P.]]
[[Category: Skene, R J.]]
[[Category: Swairjo, M A.]]
[[Category: Yang, X L.]]
[[Category: beta sheet and flanking helices]]
[[Category: class ii aminoacyl-trna synthetase]]
[[Category: helix-loop-helix motif]]

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