1riq: Difference between revisions

[[Image:1riq.gif|left|200px]]<br /><applet load="1riq" size="350" color="white" frame="true" align="right" spinBox="true"  

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.

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].  

[[Category: Lovato, M A.]]

[[Category: McRee, D E.]]

[[Category: Otero, F J.]]

[[Category: Pouplana, L Ribas de.]]

[[Category: Skene, R J.]]

[[Category: Swairjo, M A.]]

[[Category: Yang, X L.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:51:18 2008''