title: Multifaceted SlyD from Helicobacter pylori: implication in [NiFe] hydrogenase maturation.
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.
authors: Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors: Tianfan
authors: T
authors: Cheng
authors: Hongyan
authors: H
authors: Li
authors: Wei
authors: W
authors: Xia
authors: Hongzhe
authors: H
authors: Sun
mesh_terms: D003001:Cloning, Molecular; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D006864:Hydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry; D009532:Nickel / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012996:Solutions; D022021:Tacrolimus Binding Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D018832:Molecular Chaperones; D012996:Solutions; D009532:Nickel; D007501:Iron; C043296:nickel-iron hydrogenase; D006864:Hydrogenase; D022021:Tacrolimus Binding Proteins