Cocrystal structure of a tyrosyl-tRNA synthetase splicing factor with a group I intron RNA

Experimental Data Snapshot

  • Resolution: 4.50 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.235 

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Structure of a tyrosyl-tRNA synthetase splicing factor bound to a group I intron RNA.

Paukstelis, P.J.Chen, J.H.Chase, E.Lambowitz, A.M.Golden, B.L.

(2008) Nature 451: 94-97

  • DOI: https://doi.org/10.1038/nature06413
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The 'RNA world' hypothesis holds that during evolution the structural and enzymatic functions initially served by RNA were assumed by proteins, leading to the latter's domination of biological catalysis. This progression can still be seen in modern biology, where ribozymes, such as the ribosome and RNase P, have evolved into protein-dependent RNA catalysts ('RNPzymes'). Similarly, group I introns use RNA-catalysed splicing reactions, but many function as RNPzymes bound to proteins that stabilize their catalytically active RNA structure. One such protein, the Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (TyrRS; CYT-18), is bifunctional and both aminoacylates mitochondrial tRNA(Tyr) and promotes the splicing of mitochondrial group I introns. Here we determine a 4.5-A co-crystal structure of the Twort orf142-I2 group I intron ribozyme bound to splicing-active, carboxy-terminally truncated CYT-18. The structure shows that the group I intron binds across the two subunits of the homodimeric protein with a newly evolved RNA-binding surface distinct from that which binds tRNA(Tyr). This RNA binding surface provides an extended scaffold for the phosphodiester backbone of the conserved catalytic core of the intron RNA, allowing the protein to promote the splicing of a wide variety of group I introns. The group I intron-binding surface includes three small insertions and additional structural adaptations relative to non-splicing bacterial TyrRSs, indicating a multistep adaptation for splicing function. The co-crystal structure provides insight into how CYT-18 promotes group I intron splicing, how it evolved to have this function, and how proteins could have incrementally replaced RNA structures during the transition from an RNA world to an RNP world.

  • Organizational Affiliation

    Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas at Austin, Austin, Texas 78712, USA.


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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Tyrosyl-tRNA synthetase392Neurospora crassaMutation(s): 0 
Gene Names: cyt-18
Find proteins for P12063 (Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987))
Explore P12063 
Go to UniProtKB:  P12063
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12063
Sequence Annotations
  • Reference Sequence
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Entity ID: 1
MoleculeChains LengthOrganismImage
RNA (238-MER)A [auth C],
C [auth G],
E [auth K],
G [auth O]
246Twortvirus twort
Sequence Annotations
  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
RNA (5'-R(P*GP*CP*UP*U)-3')B [auth D],
D [auth H],
F [auth L],
H [auth P]
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 4.50 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.235 
  • Space Group: P 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 231.063α = 90
b = 123.525β = 90.26
c = 235.231γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
HKL-2000data collection

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-08
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Refinement description