Database accession: MF7000509
Name: FMN-dependent nitroreductase (Escherichia coli)
PDB ID: 1ds7
Experimental method: X-ray (2.06 Å)
Assembly: Homodimer
Source organism: Escherichia coli
Primary publication of the structure:
Parkinson GN, Skelly JV, Neidle S
Crystal structure of FMN-dependent nitroreductase from Escherichia coli B: a prodrug-activating enzyme.
(2000) J. Med. Chem. 43: 3624-31
PMID: 11020276
Abstract:
The FMN-dependent flavoprotein nitroreductase from Escherichia coli B (NTR) is used in cancer chemotherapy to activate a range of prodrugs. The crystal structure of this enzyme has been determined, using molecular replacement methods and refined at 2.06 A resolution. The recombinant 24-kDa enzyme was crystallized in the tetragonal space group P4(1)2(1)2, with unit cell dimensions of a = b = 57.74 A and c = 275.51 A and two molecules in the asymmetric unit. The structure has a final R factor of 20.3% (R(free) = 26.7%), for all data between the resolution ranges of 10-2.06 A, and includes 4453 protein atoms, 230 water molecules, and 2 flavin mononucleotide (FMN) molecules. The functional unit is a homodimer, which forms the asymmetric unit in the crystal structure. The tertiary structures of these two monomers and their subunit interactions are nearly identical. The molecular replacement search model, the crystal structure of the major NAD(P)H:FMN oxidoreductase of Vibrio fisheri (FRase 1), was selected on the basis of its high sequence identity to that of NTR. The final superposition of these two enzymes revealed a very similar overall fold, with variation in the structures focused around surface loops and helices near the FMN cofactor. Helix G is implicated in substrate specificity and is better resolved in the present NTR structure than in the previously reported FRase 1 structure. The FMN binding pocket is also well-resolved, showing the presence of two channels leading into the active site. The amino acid side chains and main chain atoms interacting with the FMN are well-ordered. The structure of the substrate binding pocket has been used to examine substrate specificity and enzyme kinetics for prodrugs used in antibody-directed enzyme prodrug therapy (ADEPT) and gene-directed enzyme prodrug therapy (GDEPT).
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
6,7-dihydropteridine reductase activity 6,7-dihydropteridine reductase activity
FMN binding FMN binding
identical protein binding identical protein binding
NAD(P)H dehydrogenase (quinone) activity NAD(P)H dehydrogenase (quinone) activity
oxidoreductase activity, acting on other nitrogenous compounds as donors, with NAD or NADP as acceptor oxidoreductase activity, acting on other nitrogenous compounds as donors, with NAD or NADP as acceptor
protein homodimerization activity protein homodimerization activity
Biological process:
2,4,6-trinitrotoluene catabolic process 2,4,6-trinitrotoluene catabolic process
Cellular component:
cytosol cytosol
membrane membrane
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: Oxygen-insensitive NAD(P)H nitroreductase
Source organism: Escherichia coli
Length: 217 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMDIISVALKRHSTKAFDASKKLTPEQAEQIKTLLQYSPSSTNSQPWHFIVASTEEGKARVAKSAAGNYVFNERKMLDASHVVVFCAKTAMDDVWLKLVVDQEDADGRFATPEAKAANDKGRKFFADMHRKDLHDDAEWMAKQVYLNVGNFLLGVAALGLDAVPIEGFDAAILDAEFGLKEKGYTSLVVVPVGHHSVEDFNATLPKSRLPQNITLTEV
UniProtKB AC: P38489 (positions: 1-217)
Coverage: 100%
Name: Oxygen-insensitive NAD(P)H nitroreductase
Source organism: Escherichia coli
Length: 217 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMDIISVALKRHSTKAFDASKKLTPEQAEQIKTLLQYSPSSTNSQPWHFIVASTEEGKARVAKSAAGNYVFNERKMLDASHVVVFCAKTAMDDVWLKLVVDQEDADGRFATPEAKAANDKGRKFFADMHRKDLHDDAEWMAKQVYLNVGNFLLGVAALGLDAVPIEGFDAAILDAEFGLKEKGYTSLVVVPVGHHSVEDFNATLPKSRLPQNITLTEV
UniProtKB AC: P38489 (positions: 1-217)
Coverage: 100%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: Nitroreductase family
Evidence level: Indirect evidence
Evidence coverage: The full structure participates in mutual synergistic folding.
Complex Evidence:
Authors claim that the homodimeric NAD(P)H nitroreductase is a highly intertwined dimer with the FMN binding site lying at the dimer interface (PMID:18241886). Other structures belonging to the nitroreductase family also have an extensive interaction surface wherein a large hydrophobic solvent-accessible surface becomes buried upon dimer formation, suggesting that the monomers would be unstable on their own (PMID:16229462, PMID:19436071). Domain-swapping is also typical, where the extended C-terminal region extensively interacts with the core domain of the neighbouring monomer, forming an interlocked dimer (PMID:34473996, PMID:19436071, PMID:8885832).
Chain A:
N/A
Chain B:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). Download the CIF file (.cif)
Download this entry's XML file (.xml)
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