Crystal structure of baculovirus RNA triphosphatase complexed with phosphate

Anita Changela, Alexandra Martins, Stewart Shuman, Alfonso Mondragón*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Baculovirus RNA 5′-triphosphatase (BVP) exemplifies a family of RNA-specific cysteine phosphatases that includes the RNA triphosphatase domains of metazoan and plant mRNA capping enzymes. Here we report the crystal structure of BVP in a phosphate-bound state at 1.5 Å resolution. BVP adopts the characteristic cysteine-phosphatase α/β fold and binds two phosphate ions in the active site region, one of which is proposed to mimic the phosphate of the product complex after hydrolysis of the covalent phosphoenzyme intermediate. The crystal structure highlights the role of backbone amides and side chains of the P-loop motif 118HCTHGXNRT126 in binding the cleavable phosphate and stabilizing the transition state. Comparison of the BVP structure to the apoenzyme of mammalian RNA triphosphatase reveals a concerted movement of the Arg-125 side chain (to engage the phosphate directly) and closure of an associated surface loop over the phosphate in the active site. The structure highlights a direct catalytic role of Asn-124, which is the signature P-loop residue of the RNA triphosphatase family and a likely determinant of the specificity of BVP for hydrolysis of phosphoanhydride linkages.

Original languageEnglish (US)
Pages (from-to)17848-17856
Number of pages9
JournalJournal of Biological Chemistry
Volume280
Issue number18
DOIs
StatePublished - May 6 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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