PLoS ONE (Jan 2011)

Structural analysis of papain-like NlpC/P60 superfamily enzymes with a circularly permuted topology reveals potential lipid binding sites.

  • Qingping Xu,
  • Neil D Rawlings,
  • Hsiu-Ju Chiu,
  • Lukasz Jaroszewski,
  • Heath E Klock,
  • Mark W Knuth,
  • Mitchell D Miller,
  • Marc-Andre Elsliger,
  • Ashley M Deacon,
  • Adam Godzik,
  • Scott A Lesley,
  • Ian A Wilson

DOI
https://doi.org/10.1371/journal.pone.0022013
Journal volume & issue
Vol. 6, no. 7
p. e22013

Abstract

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NlpC/P60 superfamily papain-like enzymes play important roles in all kingdoms of life. Two members of this superfamily, LRAT-like and YaeF/YiiX-like families, were predicted to contain a catalytic domain that is circularly permuted such that the catalytic cysteine is located near the C-terminus, instead of at the N-terminus. These permuted enzymes are widespread in virus, pathogenic bacteria, and eukaryotes. We determined the crystal structure of a member of the YaeF/YiiX-like family from Bacillus cereus in complex with lysine. The structure, which adopts a ligand-induced, "closed" conformation, confirms the circular permutation of catalytic residues. A comparative analysis of other related protein structures within the NlpC/P60 superfamily is presented. Permutated NlpC/P60 enzymes contain a similar conserved core and arrangement of catalytic residues, including a Cys/His-containing triad and an additional conserved tyrosine. More surprisingly, permuted enzymes have a hydrophobic S1 binding pocket that is distinct from previously characterized enzymes in the family, indicative of novel substrate specificity. Further analysis of a structural homolog, YiiX (PDB 2if6) identified a fatty acid in the conserved hydrophobic pocket, thus providing additional insights into possible function of these novel enzymes.