title: 1H and 13C NMR studies of a truncated heme domain from Chlorella vulgaris nitrate reductase: signal assignment of the heme moiety.
abstract: A water soluble truncated heme domain (a tetramer of MW = 45 kDa) of the tetrameric nitrate reductase complex from the green alga Chlorella vulgaris has been overexpressed and purified. This truncated heme domain with four identical subunits has a high redox potential (midpoint potential E1/2 = +16 mV) as compared with other heme-containing flavoproteins. We have undertaken a determination of the detailed configuration of the heme moiety in order to understand the unique electrochemical property of the heme moiety of this enzyme. We report here the study of the heme prosthetic group of the truncated heme domain by the use of 2D 1H and 13C NMR techniques. A complete signal assignment of the heme has been achieved. Our observations suggest that the heme configuration is similar to that of the crystal structure of the membrane-bound bovine liver cytochrome b5.
authors.affiliation: Department of Chemistry, University of South Florida, Tampa 33620-5250, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wei
authors.forename: L J
authors.initials: LJ
authors.lastname: Ming
authors.forename: A C
authors.initials: AC
authors.lastname: Cannons
authors.forename: L P
authors.initials: LP
authors.lastname: Solomonson
mesh_terms: D000818:Animals; D001665:Binding Sites; D002247:Carbon Isotopes; D002417:Cattle; D002708:Chlorella / Q000201:enzymology*; D015786:Cytochromes b5 / Q000737:chemistry; D006418:Heme / Q000737:chemistry* / Q000378:metabolism; D006859:Hydrogen; D008099:Liver / Q000378:metabolism; D008958:Models, Molecular; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010084:Oxidation-Reduction; D011487:Protein Conformation; D011524:Protoporphyrins / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D011524:Protoporphyrins; D006418:Heme; D006859:Hydrogen; D015786:Cytochromes b5; C028025:protoporphyrin IX; D009565:Nitrate Reductases; D050901:Nitrate Reductase