1NJ8

Crystal Structure of Prolyl-tRNA Synthetase from Methanocaldococcus janaschii

Summary for 1NJ8

• Entry DOI: 10.2210/pdb1nj8/pdb
• Related: 1NJ1 1NJ2 1NJ5 1NJ6
• Descriptor: Proline-tRNA Synthetase (2 entities in total)
• Functional Keywords: class-ii trna synthetase, ligase
• Biological source: Methanocaldococcus jannaschii
• Cellular location: Cytoplasm: Q58635
• Total number of polymer chains: 4
• Total formula weight: 215115.24

Authors

Kamtekar, S.,Kennedy, W.D.,Wang, J.,Stathopoulos, C.,Soll, D.,Steitz, T.A. (deposition date: 2002-12-30, release date: 2003-03-04, Last modification date: 2024-04-03)

Primary citation

Kamtekar, S.,Kennedy, W.D.,Wang, J.,Stathopoulos, C.,Soll, D.,Steitz, T.A.
The structural basis of cysteine aminoacylation of tRNAPro by prolyl-tRNA synthetases
Proc.Natl.Acad.Sci.USA, 100:1673-1678, 2003

PubMed Abstract: Cysteinyl-tRNA synthetase is an essential enzyme required for protein synthesis. Genes encoding this protein have not been identified in Methanocaldococcus jannaschii, Methanothermobacter thermautotrophicus, or Methanopyrus kandleri. It has previously been proposed that the prolyl-tRNA synthetase (ProRS) enzymes in these organisms recognize either proline or cysteine and can aminoacylate their cognate tRNAs through a dual-specificity mechanism. We report five crystal structures at resolutions between 2.6 and 3.2 A: apo M. jannaschii ProRS, and M. thermautotrophicus ProRS in apo form and in complex with cysteinyl-sulfamoyl-, prolyl-sulfamoyl-, and alanyl-sulfamoyl-adenylates. These aminoacyl-adenylate analogues bind to a single active-site pocket and induce an identical set of conformational changes in loops around the active site when compared with the ligand-free conformation of ProRS. The cysteinyl- and prolyl-adenylate analogues have similar, nanomolar affinities for M. thermautotrophicus ProRS. Homology modeling of tRNA onto these adenylate complexes places the 3'-OH of A76 in an appropriate position for the transfer of any of the three amino acids to tRNA. Thus, these structures explain recent biochemical experiments showing that M. jannaschii ProRS misacylates tRNA(Pro) with cysteine, and argue against the proposal that these archaeal ProRS enzymes possess the dual capacity to aminoacylate both tRNA(Pro) and tRNA(Cys) with their cognate amino acids.

PubMed: 12578991
DOI: 10.1073/pnas.0437911100

Experimental method

X-RAY DIFFRACTION (3.2 Å)