PDBsum entry 1noc

Complex (oxidoreductase/transferase)

PDB id: 1noc

Contents

Protein chains

372 a.a. *

213 a.a. *

Ligands

HEM-IMD

IMD

Waters ×140

* Residue conservation analysis

PDB id:

1noc

Name:

Complex (oxidoreductase/transferase)

Title:

Murine inducible nitric oxide synthase oxygenase domain (delta 114) complexed with type i e. Coli chloramphenicol acetyl transferase and imidazole

Structure:

Inducible nitric oxide synthase. Chain: a. Fragment: oxygenase domain 115-498. Engineered: yes. Type 1 chloramphenicol acetyltransferase. Chain: b. Ec: 2.3.1.28

Source:

Mus musculus. House mouse. Organism_taxid: 10090. Cell: macrophage. Expressed in: escherichia coli. Expression_system_taxid: 562. Escherichia coli. Organism_taxid: 562

Biol. unit:

Trimer (from PDB file)

Resolution:

2.60Å R-factor: 0.221 R-free: 0.257

Authors:

B.R.Crane,A.S.Arvai,E.D.Getzoff,D.J.Stuehr,J.A.Tainer

Key ref:

B.R.Crane et al. (1997). The structure of nitric oxide synthase oxygenase domain and inhibitor complexes. Science, 278, 425-431. PubMed id: 9334294 DOI: 10.1126/science.278.5337.425

Date:

28-Sep-97 Release date: 14-Oct-98

Protein chain

P29477  (NOS2_MOUSE) -  Nitric oxide synthase, inducible from Mus musculus

Seq: 1144 a.a.

Struc: 372 a.a.

Protein chain

P62577  (CAT_ECOLX) -  Chloramphenicol acetyltransferase from Escherichia coli

Seq: 219 a.a.

Struc: 213 a.a.

Enzyme reactions

• Enzyme class 2: Chain A: E.C.1.14.13.39 - nitric-oxide synthase (NADPH).
• Reaction: 2 L-arginine + 3 NADPH + 4 O2 + H⁺ = 2 L-citrulline + 2 nitric oxide + 3 NADP⁺ + 4 H2O

2 × L-arginine + 3 × NADPH (Bound ligand (Het Group name = IMD) matches with 41.67% similarity) + 4 × O2 + H(+) = 2 × L-citrulline + 2 × nitric oxide + 3 × NADP(+) + 4 × H2O

• Enzyme class 3: Chain B: E.C.2.3.1.28 - chloramphenicol O-acetyltransferase.
• Reaction: chloramphenicol + acetyl-CoA = chloramphenicol 3-acetate + CoA

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1126/science.278.5337.425

Science 278:425-431 (1997)

PubMed id: 9334294

The structure of nitric oxide synthase oxygenase domain and inhibitor complexes.

B.R.Crane, A.S.Arvai, R.Gachhui, C.Wu, D.K.Ghosh, E.D.Getzoff, D.J.Stuehr, J.A.Tainer.

ABSTRACT

The nitric oxide synthase oxygenase domain (NOSox) oxidizes arginine to synthesize the cellular signal and defensive cytotoxin nitric oxide (NO). Crystal structures determined for cytokine-inducible NOSox reveal an unusual fold and heme environment for stabilization of activated oxygen intermediates key for catalysis. A winged beta sheet engenders a curved alpha-beta domain resembling a baseball catcher's mitt with heme clasped in the palm. The location of exposed hydrophobic residues and the results of mutational analysis place the dimer interface adjacent to the heme-binding pocket. Juxtaposed hydrophobic O2- and polar L-arginine-binding sites occupied by imidazole and aminoguanidine, respectively, provide a template for designing dual-function inhibitors and imply substrate-assisted catalysis.

Selected figure(s)

Figure 3.
Fig. 3. Mobility, surface properties, and shape. (A) C trace of NOS[ox] 114 (cubic crystal form) colored by the crystallographic^ temperature factor (low to high B factors colored blue to red) and displayed with heme and mutation sites that affect function. Mutation sites (side chains displayed and labeled by residue number) affecting dimerization, L-Arg binding, or H[4]B binding (defined^ in Fig. 2) cluster to highly mobile (red) projecting regions. The view is rotated by about 45° from Fig. 1 about a vertical axis. (B) Solvent-accessible molecular surface of flattened^ (left) and concave (center) face. The orientation is the same^ as in (A). The exposed heme edge (gold), residues contributing to the distal pocket (cyan), and exposed conserved hydrophobic^ residues (green) (defined in Fig. 2) map to the same flattened^ face of the molecule and cluster in the regions of high mobility and mutational sensitivity shown in (A), making this surface the^ prime candidate for a symmetric dimer interface. (C) Solvent-accessible^ molecular surface of the narrow curved face. This face has few conserved exposed hydrophobic residues. The view is rotated 90° from (A) and (B) around a vertical axis.

Figure 5.
Fig. 5. Comparison of the proximal heme-binding regions of iNOS[ox] and cytochrome P450s. Structural elements contributing to the proximal heme-binding regions of iNOS[ox] 114 and P450[cam] (cyan C traces) are substantially different. Only the proximal Cys ligands (magenta bonds with yellow sulfur atoms, bound to gold^ hemes) and immediately COOH-terminal three residues (magenta C traces) have similar conformations. In iNOS[ox], Cys194 lies at the COOH-terminal end of a helix and precedes an extended^ strand, whereas in P450[cam], Cys357 lies at the NH[2]-terminal end of a helix and follows an extended^ strand. Also, these two cysteine thiolates bind opposite faces of iron protoporphyrin IX. C positions for iNOS[ox] 114 residues 194 to 197 were superimposed with P450[cam] residues 357^ to 360 and then separated for clarity.

The above figures are reprinted by permission from the AAAs: Science (1997, 278, 425-431) copyright 1997.

Figures were selected by an automated process.