title: The nitrite anion binds to human hemoglobin via the uncommon O-nitrito mode.
abstract: The nitrite anion is known to oxidize and degrade hemoglobin (Hb). Recent literature reports suggest a nitrite reductase activity for Hb, converting nitrite into nitric oxide. Surprisingly, no structural information about Hb-nitrite interactions has been reported. We have determined the crystal structure of the ferric Hb-nitrite complex at 1.80 A resolution. The nitrite ligand adopts the uncommon O-nitrito binding mode. In addition, the nitrito conformations in the alpha and beta subunits are different, reflecting subtle effects of the distal His in orienting the nitrite ligand in the O-nitrito binding mode.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Yi
authors.forename: Martin K
authors.initials: MK
authors.lastname: Safo
authors.forename: George B
authors.initials: GB
authors.lastname: Richter-Addo
mesh_terms: D000328:Adult; D000838:Anions / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D000838:Anions; D006454:Hemoglobins; D009573:Nitrites