9QOF

E.coli seryl-tRNA synthetase (Arm deletion mutant) bound to sulphamoyl seryl-adenylate analogue

Summary for 9QOF

• Entry DOI: 10.2210/pdb9qof/pdb
• Descriptor: Serine--tRNA ligase, MAGNESIUM ION, SULFATE ION, ... (5 entities in total)
• Functional Keywords: aminoacyl-trna synthetase, atp binding, translation
• Biological source: Escherichia coli K-12; More
• Total number of polymer chains: 2
• Total formula weight: 83961.57

Authors

Cusack, S.,Belrhali, H.,Price, S.,Leberman, R. (deposition date: 2025-03-26, release date: 2025-05-14)

Primary citation

Borel, F.,Vincent, C.,Leberman, R.,Hartlein, M.
Seryl-tRNA synthetase from Escherichia coli,implication of its N-terminal domain in aminoacylation activity and specificity.
Nucleic Acids Res, 22:2963-2969, 1994

PubMed Abstract: Escherichia coli seryl-tRNA synthetase (SerRS) a dimeric class II aminoacyl-tRNA synthetase with two structural domains charges specifically the five iso-acceptor tRNA(ser) as well as the tRNA(sec) (selC product) of E. coli. The N-terminal domain is a 60 A long arm-like coiled coil structure built of 2 long antiparallel a-h helices, whereas the C-terminal domain is a alpha-beta structure. A deletion of the N-terminal arm of the enzyme does not affect the amino acid activation step of the reaction, but reduces dramatically amino-acylation activity. The Kcat/Km value for the mutant enzyme is reduced by more than 4 orders of magnitude, with a nearly 30 fold increased Km value for tRNA(ser). An only slightly truncated mutant form (16 amino acids of the tip of the arm replaced by a glycine) has an intermediate aminoacylation activity. Both mutant synthetases have lost their specificity for tRNA(ser) and charge also non-cognate type 1 tRNA(s). Our results support the hypothesis that class II synthetases have evolved from an ancestral catalytic core enzyme by adding non-catalytic N-terminal or C-terminal tRNA binding (specificity) domains which act as determinants for cognate and anti-determinants for non-cognate tRNAs.

PubMed: 8065908
DOI: 10.1093/nar/22.15.2963

Experimental method

X-RAY DIFFRACTION (2.32 Å)