Identification of amino acid residues important for the phosphomannose isomerase activity of PslB in Pseudomonas aeruginosa PAO1

Hui Ju Lee, Hwan You Chang, Nandinin Venkatesan, Hwei-Ling Peng*

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Phosphomannose isomerase (PMI) plays a pivotal role in biosynthesis of GDP-mannose, an important precursor of many polysaccharides. We demonstrate in this study that Pseudomonas aeruginosa pslB encodes a protein with GDP-mannose pyrophosphorylase/PMI dual activities. The PMI activity is Co2+-dependent and could be inhibited by GDP-mannose in a competitive manner. Furthermore, the activity could be inactivated by 2,3-butanedione suggesting the presence of a catalytic Arg residue. Site-specific mutations at R373, R472, R479, E410, H411, N433 and E458 increase the KM approximately 8-20-fold. The PMI activity of PslB was completely diminished with a R408K or R408A, reflecting the importance of this residue in catalysis. Overall, these results provide a basis for understanding the catalytic mechanism of PMI.

Original languageEnglish
Pages (from-to)3479-3483
Number of pages5
JournalFEBS Letters
Volume582
Issue number23-24
DOIs
StatePublished - 15 Oct 2008

Keywords

  • GDP-mannose pyrophosphorylase
  • Phosphomannose isomerase
  • Pseudomonas aeruginosa
  • Site-directed mutagenesis
  • pslB

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