title: Crystal structure of hydrogenase maturating endopeptidase HycI from Escherichia coli.
abstract: The maturation of [NiFe]-hydrogenases is a catalyzed process involving the activities of at least seven proteins. The last step consists of the endoproteolytic cleavage of the precursor of the large subunit, after the [NiFe]-metal center has been assembled. The HycI endopeptidase is involved in the C-terminal processing of HycE, the large subunit of hydrogenase 3 from Escherichia coli. Although HycI has been well characterized biochemically, the crystallization of the protein has been quite challenging. Here, we present the crystal structure of HycI at 1.70 A resolution. The crystal structure resembles the recently reported solution structure (NMR) of the same protein and the holo-HyPD structure of the same family, but a significant conformational change is observed at the L5 loop, as compared with the solution structures of HycI and HyPD. In our crystal structure, three specific metal binding sites (Ca1-3) were identified and these metal ions are possibly involved in the C-terminal cleavage of HycE.
authors.affiliation: RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan. tskvel@spring8.or.jp
authors.forename: Thirumananseri
authors.initials: T
authors.lastname: Kumarevel
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Bessho
authors.forename: Akeo
authors.initials: A
authors.lastname: Shinkai
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D002118:Calcium / Q000737:chemistry; D018360:Crystallography, X-Ray; D010450:Endopeptidases / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology*; D009532:Nickel / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D009532:Nickel; D010450:Endopeptidases; C100872:HycI protease; D002118:Calcium