Characterization of a monothiol glutaredoxin encoded by Chlorella virus PBCV-1

Lisa A. Fitzgerald, Yuanzheng Zhang, Gentry Lewis, James L. Van Etten

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Annotation of the 330-kb Chlorella virus PBCV-1 genome identified a 237 nucleotide gene (a438l) that codes for a protein with ~35% amino acid identity to glutaredoxins (Grx) found in other organisms. The PBCV-1 protein resembles classical Grxs in both size (9 kDa) and location of the active site (N-terminus). However, the PBCV-1 Grx is unusual because it contains a monothiol active site (CPYS) rather than the typical dithiol active site (CPYC). To examine this unique active site, four site-specific mutants (CPYC, CPYA, SPYC, and SPYS) were constructed to determine if the N-terminal cysteine is necessary for enzyme activity. Wild type and both mutants containing N-terminal cysteines catalyzed the reduction of disulfides in a coupled system with GSH, NADPH, and glutathione reductase. However, both mutants with an altered N-terminal cysteine were inactive. The grx gene is common in the Chlorella viruses. Molecular phylogenetic analyses of the PBCV-1 enzyme support its relatedness to those from other Chlorella viruses and yet demonstrate the divergence of the Grx molecule.

Original languageEnglish (US)
Pages (from-to)418-426
Number of pages9
JournalVirus Genes
Issue number3
StatePublished - Nov 2009


  • Chlorella viruses
  • Classical glutaredoxin
  • Monothiol glutaredoxin
  • Phycodnaviridae
  • Virus PBCV-1

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Virology


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