title: Structural basis for the inhibition mechanism of human cystathionine gamma-lyase, an enzyme responsible for the production of H(2)S.
abstract: Impairment of the formation or action of hydrogen sulfide (H(2)S), an endogenous gasotransmitter, is associated with various diseases, such as hypertension, diabetes mellitus, septic and hemorrhagic shock, and pancreatitis. Cystathionine beta-synthase and cystathionine gamma-lyase (CSE) are two pyridoxal-5'-phosphate (PLP)-dependent enzymes largely responsible for the production of H(2)S in mammals. Inhibition of CSE by DL-propargylglycine (PAG) has been shown to alleviate disease symptoms. Here we report crystal structures of human CSE (hCSE), in apo form, and in complex with PLP and PLP.PAG. Structural characterization, combined with biophysical and biochemical studies, provides new insights into the inhibition mechanism of hCSE-mediated production of H(2)S. Transition from the open form of apo-hCSE to the closed PLP-bound form reveals large conformational changes hitherto not reported. In addition, PAG binds hCSE via a unique binding mode, not observed in PAG-enzyme complexes previously. The interaction of PAG-hCSE was not predicted based on existing information from known PAG complexes. The structure of hCSE.PLP.PAG complex highlights the particular importance of Tyr(114) in hCSE and the mechanism of PAG-dependent inhibition of hCSE. These results provide significant insights, which will facilitate the structure-based design of novel inhibitors of hCSE to aid in the development of therapies for diseases involving disorders of sulfur metabolism.
authors.affiliation: Department of Biological Sciences, National University of Singapore, 117543 Singapore.
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
authors.forename: Ruairi
authors.initials: R
authors.lastname: Collins
authors.affiliation: Department of Chemistry, National University of Singapore, 117543 Singapore.
authors.forename: Shufen
authors.initials: S
authors.lastname: Huang
authors.affiliation: Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
authors.forename: Lovisa
authors.initials: L
authors.lastname: Holmberg-Schiavone
authors.affiliation: Department of Biological Sciences, National University of Singapore, 117543 Singapore.
authors.forename: Ganesh S
authors.initials: GS
authors.lastname: Anand
authors.affiliation: Department of Chemistry, National University of Singapore, 117543 Singapore.
authors.forename: Choon-Hong
authors.initials: CH
authors.lastname: Tan
authors.affiliation: Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
authors.forename: Susanne
authors.initials: S
authors.lastname: van-den-Berg
authors.affiliation: Department of Biochemistry, National University of Singapore, 117543 Singapore.
authors.forename: Lih-Wen
authors.initials: LW
authors.lastname: Deng
authors.affiliation: Pharmaceutical Sciences Division, King's College, University of London, London, United Kingdom.
authors.forename: Philip K
authors.initials: PK
authors.lastname: Moore
authors.affiliation: Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden. Electronic address: tobias.karlberg@ki.se.
authors.forename: Tobias
authors.initials: T
authors.lastname: Karlberg
authors.affiliation: Department of Biological Sciences, National University of Singapore, 117543 Singapore. Electronic address: dbsjayar@nus.edu.sg.
authors.forename: J
authors.initials: J
authors.lastname: Sivaraman
mesh_terms: D001703:Biophysics; D002151:Calorimetry; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003542:Cystathionine gamma-Lyase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D003542:Cystathionine gamma-Lyase; D006862:Hydrogen Sulfide