Structural basis for the inhibition mechanism of human cystathionine gamma-lyase, an enzyme responsible for the production of H(2)S.
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.
Sun
Qingxiang
Q
Department of Biological Sciences, National University of Singapore, 117543 Singapore.
Collins
Ruairi
R
Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
Huang
Shufen
S
Department of Chemistry, National University of Singapore, 117543 Singapore.
Holmberg-Schiavone
Lovisa
L
Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
Anand
Ganesh S
GS
Department of Biological Sciences, National University of Singapore, 117543 Singapore.
Tan
Choon-Hong
CH
Department of Chemistry, National University of Singapore, 117543 Singapore.
van-den-Berg
Susanne
S
Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden.
Deng
Lih-Wen
LW
Department of Biochemistry, National University of Singapore, 117543 Singapore.
Moore
Philip K
PK
Pharmaceutical Sciences Division, King's College, University of London, London, United Kingdom.
Karlberg
Tobias
T
Structural Genomics Consortium, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-17177, Sweden. Electronic address: tobias.karlberg@ki.se.
Sivaraman
J
J
Department of Biological Sciences, National University of Singapore, 117543 Singapore. Electronic address: dbsjayar@nus.edu.sg.
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
D003542:Cystathionine gamma-Lyase; D006862:Hydrogen Sulfide