Ana P G Silva

Publications (2)6.85 Total impact

• Source

  Available from: Chyan Leong Ng

  Article: Structure and activity of a novel archaeal β-CASP protein with N-terminal KH domains.

  Ana P G Silva, Maria Chechik, Robert T Byrne, David G Waterman, C Leong Ng, Eleanor J Dodson, Eugene V Koonin, Alfred A Antson, Callum Smits
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  ABSTRACT: MTH1203, a β-CASP metallo-β-lactamase family nuclease from the archaeon Methanothermobacter thermautotrophicus, was identified as a putative nuclease that might contribute to RNA processing. The crystal structure of MTH1203 reveals that, in addition to the metallo-β-lactamase nuclease and the β-CASP domains, it contains two contiguous KH domains that are unique to MTH1203 and its orthologs. RNA-binding experiments indicate that MTH1203 preferentially binds U-rich sequences with a dissociation constant in the micromolar range. In vitro nuclease activity assays demonstrated that MTH1203 is a zinc-dependent nuclease. MTH1203 is also shown to be a dimer and, significantly, this dimerization enhances the nuclease activity. Transcription termination in archaea produces mRNA transcripts with U-rich 3' ends that could be degraded by MTH1203 considering its RNA-binding specificity. We hypothesize that this nuclease degrades mRNAs of proteins targeted for degradation and so regulates archaeal RNA turnover, possibly in concert with the exosome.
  Structure 05/2011; 19(5):622-32. · 6.35 Impact Factor
• Article: Expression, purification, crystallization and preliminary X-ray studies of the TAN1 orthologue from Methanothermobacter thermautotrophicus.

  Ana P G Silva, Robert T Byrne, Maria Chechik, Callum Smits, David G Waterman, Alfred A Antson
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  ABSTRACT: MTH909 is the Methanothermobacter thermautotrophicus orthologue of Saccharomyces cerevisiae TAN1, which is required for N(4)-acetylcytidine formation in tRNA. The protein consists of an N-terminal near-ferredoxin-like domain and a C-terminal THUMP domain. Unlike most other proteins containing the THUMP domain, TAN1 lacks any catalytic domains and has been proposed to form a complex with a catalytic protein that is capable of making base modifications. MTH909 has been cloned, overexpressed and purified. The molecule exists as a monomer in solution. X-ray data were collected to 2.85 A resolution from a native crystal belonging to space group P6(1)22 (or P6(5)22), with unit-cell parameters a = 69.9, c = 408.5 A.
  Acta Crystallographica Section F Structural Biology and Crystallization Communications 12/2008; 64(Pt 11):1083-6. · 0.51 Impact Factor