3ONZ

Human tetrameric hemoglobin: proximal nitrite ligand at beta

Summary for 3ONZ

• Entry DOI: 10.2210/pdb3onz/pdb
• Related: 3OO4 3OO5
• Descriptor: Hemoglobin subunit alpha, Hemoglobin subunit beta, PROTOPORPHYRIN IX CONTAINING FE, ... (6 entities in total)
• Functional Keywords: nitrite, human hemoglobin, oxygen transport
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 2
• Total formula weight: 32734.09

Authors

Yi, J.,Thormas, L.M.,Safo, M.K.,Musayev, F.N.,Richter-Addo, G.B. (deposition date: 2010-08-30, release date: 2011-09-07, Last modification date: 2023-09-06)

Primary citation

Yi, J.,Thomas, L.M.,Musayev, F.N.,Safo, M.K.,Richter-Addo, G.B.
Crystallographic Trapping of Heme Loss Intermediates during the Nitrite-Induced Degradation of Human Hemoglobin.
Biochemistry, 50:8323-8332, 2011

PubMed Abstract: Heme is an important cofactor in a large number of essential proteins and is often involved in small molecule binding and activation. Loss of heme from proteins thus negatively affects the function of these proteins but is also an important component of iron recycling. The characterization of intermediates that form during the loss of heme from proteins has been problematic, in a large part, because of the instability of such intermediates. We have characterized, by X-ray crystallography, three compounds that form during the nitrite-induced degradation of human α(2)β(2) hemoglobin (Hb). The first is an unprecedented complex that exhibits a large β heme displacement of 4.8 Å toward the protein exterior; the heme displacement is stabilized by the binding of the distal His residue to the heme Fe, which in turn allows for the unusual binding of an exogenous ligand on the proximal face of the heme. We have also structurally characterized complexes that display regiospecific nitration of the heme at the 2-vinyl position; we show that heme nitration is not a prerequisite for heme loss. Our results provide structural insight into a possible pathway for nitrite-induced loss of heme from human Hb.

PubMed: 21863786
DOI: 10.1021/bi2009322

Experimental method

X-RAY DIFFRACTION (2.087 Å)