PDBsum entry 1npf

Oxygen storage/transport

PDB id: 1npf

Contents

Protein chain

152 a.a. *

Ligands

SO4 ×2

HEM-_NO

Waters ×118

* Residue conservation analysis

PDB id:

1npf

Name:

Oxygen storage/transport

Title:

Myoglobin (horse heart) wild-type complexed with nitric oxide

Structure:

Myoglobin. Chain: a. Other_details: animal oxygen storage

Source:

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

Resolution:

1.90Å R-factor: 0.199 R-free: 0.247

Authors:

D.M.Copeland,A.H.West,G.B.Richter-Addo

Key ref:

D.M.Copeland et al. (2003). Crystal structures of ferrous horse heart myoglobin complexed with nitric oxide and nitrosoethane. Proteins, 53, 182-192. PubMed id: 14517970 DOI: 10.1002/prot.10495

Date:

17-Jan-03 Release date: 11-Nov-03

Protein chain

P68082  (MYG_HORSE) -  Myoglobin from Equus caballus

Seq: 154 a.a.

Struc: 153 a.a.

DOI no: 10.1002/prot.10495

Proteins 53:182-192 (2003)

PubMed id: 14517970

Crystal structures of ferrous horse heart myoglobin complexed with nitric oxide and nitrosoethane.

D.M.Copeland, A.H.West, G.B.Richter-Addo.

ABSTRACT

The interactions of nitric oxide (NO) and organic nitroso compounds with heme proteins are biologically important, and adduct formation between NO-containing compounds and myoglobin (Mb) have served as prototypical systems for studies of these interactions. We have prepared crystals of horse heart (hh) MbNO from nitrosylation of aqua-metMb crystals, and we have determined the crystal structure of hh MbNO at a resolution of 1.9 A. The Fe-N-O angle of 147 degrees in hh MbNO is larger than the corresponding 112 degrees angle previously determined from the crystal structure of sperm whale MbNO (Brucker et al., Proteins 1998;30:352-356) but is similar to the 150 degrees angle determined from a MS XAFS study of a frozen solution of hh MbNO (Rich et al., J Am Chem Soc 1998;120:10827-10836). The Fe-N(O) bond length of 2.0 A (this work) is longer than the 1.75 A distance determined from the XAFS study and suggests distal pocket influences on FeNO geometry. The nitrosyl N atom is located 3.0 A from the imidazole N(epsilon) atom of the distal His64 residue, suggesting electrostatic stabilization of the FeNO moiety by His64. The crystal structure of the nitrosoethane adduct of ferrous hh Mb was determined at a resolution of 1.7 A. The nitroso O atom of the EtNO ligand is located 2.7 A from the imidazole N(epsilon) atom of His64, suggesting a hydrogen bond interaction between these groups. To the best of our knowledge, the crystal structure of hh Mb(EtNO) is the first such determination of a nitrosoalkane adduct of a heme protein.

Selected figure(s)

Figure 1.
Figure 1. a: F[o]-F[c] omit electron density map contoured at 3 and final model showing a side view of the heme environment in hh MbNO. The dashed yellow line represents the 3.0 Å distance between N^ of the distal His64 residue and the N atom of the nitrosyl ligand. Carbon, oxygen, nitrogen, and iron atoms are colored gray, red, blue, and brown, respectively. b: Top view of the heme in hh MbNO, with the NO ligand on the side of the porphyrin ring facing the viewer. The coloring scheme is the same as in (a) with the exception of the proximal His93 ligand, which is shown in yellow for clarity.

Figure 3.
Figure 3. a: F[o]-F[c] omit electron density map contoured at 3 and final model showing a side view of the heme environment in hh Mb(EtNO). The dashed yellow line represents a 2.7 Å distance between the N^ atom of the distal His64 residue and the O atom of the nitroso group. b: View of the heme environment showing the off-axis tilt of the nitrosoethane ligand. The view is along the nitrosoethane CNO plane. c: Top view of the heme environment in hh Mb(EtNO). The EtNO ligand is on the side of the porphyrin ring facing the viewer.

The above figures are reprinted by permission from John Wiley & Sons, Inc.: Proteins (2003, 53, 182-192) copyright 2003.

Figures were selected by an automated process.