1d2r

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Tryptophan--tRNA_ligase Tryptophan--tRNA ligase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.2 6.1.1.2] </span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of ligand-free tryptophanyl-tRNA synthetase (TrpRS) was solved at 2.9 A using a combination of molecular replacement and maximum-entropy map/phase improvement. The dimeric structure (R = 23.7, Rfree = 26.2) is asymmetric, unlike that of the TrpRS tryptophanyl-5'AMP complex (TAM; Doublie S, Bricogne G, Gilmore CJ, Carter CW Jr, 1995, Structure 3:17-31). In agreement with small-angle solution X-ray scattering experiments, unliganded TrpRS has a conformation in which both monomers open, leaving only the tryptophan-binding regions of their active sites intact. The amino terminal alphaA-helix, TIGN, and KMSKS signature sequences, and the distal helical domain rotate as a single rigid body away from the dinucleotide-binding fold domain, opening the AMP binding site, seen in the TAM complex, into two halves. Comparison of side-chain packing in ligand-free TrpRS and the TAM complex, using identification of nonpolar nuclei (Ilyin VA, 1994, Protein Eng 7:1189-1195), shows that significant repacking occurs between three relatively stable core regions, one of which acts as a bearing between the other two. These domain rearrangements provide a new structural paradigm that is consistent in detail with the "induced-fit" mechanism proposed for TyrRS by Fersht et al. (Fersht AR, Knill-Jones JW, Beduelle H, Winter G, 1988, Biochemistry 27:1581-1587). Coupling of ATP binding determinants associated with the two catalytic signature sequences to the helical domain containing the presumptive anticodon-binding site provides a mechanism to coordinate active-site chemistry with relocation of the major tRNA binding determinants.

2.9 A crystal structure of ligand-free tryptophanyl-tRNA synthetase: domain movements fragment the adenine nucleotide binding site.,Ilyin VA, Temple B, Hu M, Li G, Yin Y, Vachette P, Carter CW Jr Protein Sci. 2000 Feb;9(2):218-31. PMID:10716174<ref>PMID:10716174</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Carter, C W]]

[[Category: Ilyin, V A]]

[[Category: Trpr]]