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 (HpSlyD?C). HpSlyD?C 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 ?-sheet with an ?-helix on one side, whereas the IF domain folds into a four-stranded antiparallel ?-sheet accompanied by a short ?-helix. Intact H. pylori SlyD binds both Ni(2+) and Zn(2+), with dissociation constants of 2.74 and 3.79 ?M 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.

SUBMITTER: Cheng T 

PROVIDER: S-EPMC3292732 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature