Multifaceted SlyD from Helicobacter pylori: implication in [NiFe] hydrogenase maturation

J Biol Inorg Chem. 2012 Mar;17(3):331-43. doi: 10.1007/s00775-011-0855-y. Epub 2011 Nov 2.

Abstract

SlyD belongs to the FK506-binding protein (FKBP) family with both peptidylprolyl isomerase (PPIase) and chaperone activities, and is considered to be a ubiquitous cytosolic protein-folding facilitator in bacteria. It possesses a histidine- and cysteine-rich C-terminus binding to selected divalent metal ions (e.g., Ni(2+), Zn(2+)), which is important for its involvement in the maturation processes of metalloenzymes. We have determined the solution structure of C-terminus-truncated SlyD from Helicobacter pylori (HpSlyDΔC). HpSlyDΔC folds into two well-separated, orientation-independent domains: the PPIase-active FKBP domain and the chaperone-active insert-in-flap (IF) domain. The FKBP domain consists of a four-stranded antiparallel β-sheet with an α-helix on one side, whereas the IF domain folds into a four-stranded antiparallel β-sheet accompanied by a short α-helix. Intact H. pylori SlyD binds both Ni(2+) and Zn(2+), with dissociation constants of 2.74 and 3.79 μM respectively. Intriguingly, binding of Ni(2+) instead of Zn(2+) induces protein conformational changes around the active sites of the FKBP domain, implicating a regulatory role of nickel. The twin-arginine translocation (Tat) signal peptide from the small subunit of [NiFe] hydrogenase (HydA) binds the protein at the IF domain. Nickel binding and the recognition of the Tat signal peptide by the protein suggest that SlyD participates in [NiFe] hydrogenase maturation processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Helicobacter pylori / enzymology*
  • Humans
  • Hydrogenase / chemistry
  • Hydrogenase / genetics
  • Hydrogenase / metabolism*
  • Iron / chemistry*
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Chaperones / chemistry
  • Nickel / chemistry*
  • Protein Structure, Secondary
  • Solutions
  • Tacrolimus Binding Proteins / chemistry*
  • Tacrolimus Binding Proteins / genetics

Substances

  • Molecular Chaperones
  • Solutions
  • Nickel
  • Iron
  • nickel-iron hydrogenase
  • Hydrogenase
  • Tacrolimus Binding Proteins