title: The role of tryptophan in the ferredoxin-dependent nitrite reductase of spinach.
abstract: A system has been developed for expressing a His-tagged form of the ferredoxin-dependent nitrite reductase of spinach in Escherichia coli. The catalytic and spectral properties of the His-tagged, recombinant enzyme are similar, but not identical, to those previously observed for nitrite reductase isolated directly from spinach leaf. A detailed comparison of the spectral, catalytic and fluorescence properties of nitrite reductase variants, in which each of the enzyme's eight tryptophan residues has been replaced using site-directed mutagenesis by either aromatic or non-aromatic amino acids, has been used to examine possible roles for tryptophan residues in the reduction of nitrite to ammonia catalyzed by the enzyme.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University, 1 Circle Drive, Lubbock, TX 79409-1061, USA.
authors.forename: Jatindra N
authors.initials: JN
authors.lastname: Tripathy
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hirasawa
authors.forename: Sung-Kun
authors.initials: SK
authors.lastname: Kim
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Setterdahl
authors.forename: James P
authors.initials: JP
authors.lastname: Allen
authors.forename: David B
authors.initials: DB
authors.lastname: Knaff
mesh_terms: D002942:Circular Dichroism; D005288:Ferredoxins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009572:Nitrite Reductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D013053:Spectrophotometry; D018724:Spinacia oleracea / Q000201:enzymology*; D014364:Tryptophan / Q000235:genetics / Q000378:metabolism*
chemical_list: D005288:Ferredoxins; D014364:Tryptophan; D009572:Nitrite Reductases