title: Analysis of the E. coli NifS CsdB protein at 2.0 A reveals the structural basis for perselenide and persulfide intermediate formation.
abstract: The Escherichia coli NifS CsdB protein is a member of the homodimeric pyridoxal 5'-phosphate (PLP)-dependent family of enzymes. These enzymes are capable of decomposing cysteine or selenocysteine into L-alanine and sulfur or selenium, respectively. E. coli NifS CsdB has a high specificity for L-selenocysteine in comparison to l-cysteine, suggesting a role for this enzyme is selenium metabolism. The 2.0 A crystal structure of E. coli NifS CsdB reveals a high-resolution view of the active site of this enzyme in apo-, persulfide, perselenide, and selenocysteine-bound intermediates, suggesting a mechanism for the stabilization of the enzyme persulfide and perselenide intermediates during catalysis, a necessary intermediate in the formation of sulfur and selenium containing metabolites.
authors.affiliation: Biochemistry Department and Structural Biology Program, Weill Medical College of Cornell University, New York, NY 10021, USA. lima@pinky.med.cornell.edu
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lima
mesh_terms: D001051:Apoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D008024:Ligands; D008190:Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016566:Organoselenium Compounds / Q000378:metabolism*; D011487:Protein Conformation; D017279:Selenocysteine / Q000378:metabolism; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D001051:Apoenzymes; D001426:Bacterial Proteins; D004220:Disulfides; D008024:Ligands; D016566:Organoselenium Compounds; D013440:Sulfides; C080001:nifS protein, Bacteria; C051552:persulfides; D017279:Selenocysteine; C116840:cysteine persulfide; D008190:Lyases; C034278:selenocysteine lyase; D003545:Cysteine