PDBsum entry 4uqs

Oxidoreductase

PDB id: 4uqs

Contents

Protein chain

362 a.a.

Ligands

HEM

INE

PEG

Metals

_CL

Waters ×138

PDB id:

4uqs

Name:

Oxidoreductase

Title:

Structure of bacillus subtilis nitric oxide synthase in complex with 3-bromo-7-nitroindazole

Structure:

Nitric oxide synthase oxygenase. Chain: a. Synonym: nitric oxide synthase, nosoxy-like protein. Engineered: yes. Mutation: yes

Source:

Bacillus subtilis. Organism_taxid: 1423. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.15Å R-factor: 0.231 R-free: 0.283

Authors:

J.K.Holden,T.L.Poulos

Key ref:

J.K.Holden et al. (2014). Identification of redox partners and development of a novel chimeric bacterial nitric oxide synthase for structure activity analyses. J Biol Chem, 289, 29437-29445. PubMed id: 25194416 DOI: 10.1074/jbc.M114.595165

Date:

24-Jun-14 Release date: 17-Sep-14

Protein chain

O34453  (NOSO_BACSU) -  Nitric oxide synthase oxygenase from Bacillus subtilis (strain 168)

Seq: 363 a.a.

Struc: 362 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.1.14.14.47 - nitric-oxide synthase (flavodoxin).
• Reaction: 3 reduced [flavodoxin] + 2 L-arginine + 4 O2 = 3 oxidized [flavodoxin] + 2 L-citrulline + 2 nitric oxide + 4 H2O + 5 H⁺
• Cofactor: 5,6,7,8-tetrahydrobiopterin; Ferriheme b

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

reference

DOI no: 10.1074/jbc.M114.595165

J Biol Chem 289:29437-29445 (2014)

PubMed id: 25194416

Identification of redox partners and development of a novel chimeric bacterial nitric oxide synthase for structure activity analyses.

J.K.Holden, N.Lim, T.L.Poulos.

ABSTRACT

Production of nitric oxide (NO) by nitric oxide synthase (NOS) requires electrons to reduce the heme iron for substrate oxidation. Both FAD and FMN flavin groups mediate the transfer of NADPH derived electrons to NOS. Unlike mammalian NOS that contain both FAD and FMN binding domains within a single polypeptide chain, bacterial NOS is only composed of an oxygenase domain and must rely on separate redox partners for electron transfer and subsequent activity. Here, we report on the native redox partners for Bacillus subtilis NOS (bsNOS) and a novel chimera that promotes bsNOS activity. By identifying and characterizing native redox partners, we were also able to establish a robust enzyme assay for measuring bsNOS activity and inhibition. This assay was used to evaluate a series of established NOS inhibitors. Using the new assay for screening small molecules led to the identification of several potent inhibitors for which bsNOS-inhibitor crystal structures were determined. In addition to characterizing potent bsNOS inhibitors, substrate binding was also analyzed using isothermal titration calorimetry giving the first detailed thermodynamic analysis of substrate binding to NOS.