PDBsum entry 2v1h

Oxygen transport

PDB id: 2v1h

Contents

Protein chain

153 a.a. *

Ligands

HEM

SO4 ×2

GOL ×4

Waters ×184

* Residue conservation analysis

PDB id:

2v1h

Name:

Oxygen transport

Title:

Crystal structure of radiation-induced metmyoglobin - aqua ferrous myoglobin at ph 5.2

Structure:

Myoglobin. Chain: a. Other_details: fe(ii)-oh2

Source:

Equus caballus. Horse. Organism_taxid: 9796. Organ: heart

Resolution:

1.30Å R-factor: 0.133 R-free: 0.165

Authors:

H.-P.Hersleth,C.H.Gorbitz,K.K.Andersson

Key ref:

H.P.Hersleth et al. (2007). Crystallographic and spectroscopic studies of peroxide-derived myoglobin compound II and occurrence of protonated FeIV O. J Biol Chem, 282, 23372-23386. PubMed id: 17565988 DOI: 10.1074/jbc.M701948200

Date:

24-May-07 Release date: 12-Jun-07

Protein chain

P68082  (MYG_HORSE) -  Myoglobin from Equus caballus

Seq: 154 a.a.

Struc: 153 a.a.

DOI no: 10.1074/jbc.M701948200

J Biol Chem 282:23372-23386 (2007)

PubMed id: 17565988

Crystallographic and spectroscopic studies of peroxide-derived myoglobin compound II and occurrence of protonated FeIV O.

H.P.Hersleth, T.Uchida, A.K.Røhr, T.Teschner, V.Schünemann, T.Kitagawa, A.X.Trautwein, C.H.Görbitz, K.K.Andersson.

ABSTRACT

High resolution crystal structures of myoglobin in the pH range 5.2-8.7 have been used as models for the peroxide-derived compound II intermediates in heme peroxidases and oxygenases. The observed Fe-O bond length (1.86-1.90 A) is consistent with that of a single bond. The compound II state of myoglobin in crystals was controlled by single-crystal microspectrophotometry before and after synchrotron data collection. We observe some radiation-induced changes in both compound II (resulting in intermediate H) and in the resting ferric state of myoglobin. These radiation-induced states are quite unstable, and compound II and ferric myoglobin are immediately regenerated through a short heating above the glass transition temperature (<1 s) of the crystals. It is unclear how this influences our compound II structures compared with the unaffected compound II, but some crystallographic data suggest that the influence on the Fe-O bond distance is minimal. Based on our crystallographic and spectroscopic data we suggest that for myoglobin the compound II intermediate consists of an Fe(IV)-O species with a single bond. The presence of Fe(IV) is indicated by a small isomer shift of delta = 0.07 mm/s from Mössbauer spectroscopy. Earlier quantum refinements (crystallographic refinement where the molecular-mechanics potential is replaced by a quantum chemical calculation) and density functional theory calculations suggest that this intermediate H species is protonated.

Selected figure(s)

Figure 5.
FIGURE 5. Crystal structures of the heme region. Structures for radiation-induced Mb compound II (resolutions of 1.35, 1.30, and 1.20 Å, respectively) at pH 5.2, 6.8, and 8.7, radiation-induced ferric Mb (resolutions of 1.30, 1.20, and 1.40 Å, respectively) at pH 5.2, 6.8, and 8.7, and ferrous deoxyMb (resolution of 1.25 Å) are shown with the electron density 2F[o] - F[c] map (contoured at 1 in gold), the final F[o] - F[c] map (contoured at +3 in green and at -3 in red), and electron density difference F[o] - F[c] maps with the iron-ligated oxygen atom (or water above the heme ring in deoxyMb) omitted for map calculation (contoured at 5 in magenta for the iron-ligated oxygen atom and at 4.5 for the water in deoxyMb).

Figure 6.
FIGURE 6. Crystal structures of the heme region of the radiation-induced Mb compound II crystal structure at pH 5. 2 (red), 6.8 (green), and 8.7 (blue) compared with each other and to the radiation-induced ferric Mb structures (pale colors). The Fe–O distances, the iron to proximal His distances, the iron to distal His distances, and the hydrogen bond distances between the oxygen atom and the distal His are shown.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 23372-23386) copyright 2007.

Figures were selected by the author.