1d2r: Difference between revisions
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'''2.9 A CRYSTAL STRUCTURE OF LIGAND-FREE TRYPTOPHANYL-TRNA SYNTHETASE: DOMAIN MOVEMENTS FRAGMENT THE ADENINE NUCLEOTIDE BINDING SITE.''' | '''2.9 A CRYSTAL STRUCTURE OF LIGAND-FREE TRYPTOPHANYL-TRNA SYNTHETASE: DOMAIN MOVEMENTS FRAGMENT THE ADENINE NUCLEOTIDE BINDING SITE.''' | ||
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[[Category: Ilyin, V A.]] | [[Category: Ilyin, V A.]] | ||
[[Category: Jr., C W.Carter.]] | [[Category: Jr., C W.Carter.]] | ||
[[Category: | [[Category: Aar]] | ||
[[Category: | [[Category: Class i trna synthetase]] | ||
[[Category: | [[Category: Induced fit]] | ||
[[Category: | [[Category: Trpr]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:23:08 2008'' | |||
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Revision as of 13:23, 2 May 2008
2.9 A CRYSTAL STRUCTURE OF LIGAND-FREE TRYPTOPHANYL-TRNA SYNTHETASE: DOMAIN MOVEMENTS FRAGMENT THE ADENINE NUCLEOTIDE BINDING SITE.
OverviewOverview
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.
About this StructureAbout this Structure
1D2R is a Single protein structure of sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA.
ReferenceReference
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 Page seeded by OCA on Fri May 2 13:23:08 2008