1FXX: Exonuclease I

The structure of exonuclease I suggests how processivity is achieved. Determined by X-ray diffraction at 2.4 Å resolution. Released 6 Dec 2000.

Method: X-ray diffraction
Resolution: 2.4 Å
Organism: Escherichia coli
Chains: 1
Atoms: 3,842
Mol. weight: 55.72 kDa
Ligands: PO4, MG
Released: 6 Dec 2000

Explore 1FXX in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1FXX contains 29 α-helices and 13 β-strands across 1 chain. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 29 helices, 13 β-strands

Element	Residues	Length	Sheet
β-strand	10-18	9	1
β-strand	28-36	9	1
β-strand	42	1	1
β-strand	47-50	4	1
β-strand	51	1	2
α-helix	52-54	3
α-helix	61-67	7
α-helix	71-77	7
β-strand	79	1	2
α-helix	81-92	12
β-strand	97-101	5	1
α-helix	108-118	11
α-helix	125-127	3
β-strand	133-136	4	1
α-helix	137-147	11
α-helix	166-171	6
α-helix	183-200	18
α-helix	202-210	9
α-helix	214-220	7
β-strand	229-232	4	3
α-helix	234-236	3
α-helix	238-240	3
β-strand	243-251	9	3
β-strand	258-263	6	3
α-helix	269-273	5
α-helix	276-285	10
β-strand	298-302	5	3
β-strand	308-311	4	3
α-helix	312-314	3
α-helix	317-323	7
α-helix	327-339	13
α-helix	342-351	10
α-helix	363-365	3
α-helix	367-369	3
α-helix	371-373	3
α-helix	374-385	12
α-helix	388-390	3
α-helix	402-414	13
α-helix	416-418	3
α-helix	421-434	14
α-helix	437-453	17
α-helix	458-475	18

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Exonuclease I	A	protein	482	Escherichia coli	P04995 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>1FXX_1 EXONUCLEASE I (chains A)
MMNDGKQQSTFLFHDYETFGTHPALDRPAQFAAIRTDSEFNVIGEPEVFYCKPADDYLPQ
PGAVLITGITPQEARAKGENEAAFAARIHSLFTVPKTCILGYNNVRFDDEVTRNIFYRNF
YDPYAWSWQHDNSRWDLLDVMRACYALRPEGINWPENDDGLPSFRLEHLTKANGIEHSNA
HDAMADVYATIAMAKLVKTRQPRLFDYLFTHRNKHKLMALIDVPQMKPLVHVSGMFGAWR
GNTSWVAPLAWHPENRNAVIMVDLAGDISPLLELDSDTLRERLYTAKTDLGDNAAVPVKL
VHINKCPVLAQANTLRPEDADRLGINRQHCLDNLKILRENPQVREKVVAIFAEAEPFTPS
DNVDAQLYNGFFSDADRAAMKIVLETEPRNLPALDITFVDKRIEKLLFNYRARNFPGTLD
YAEQQRWLEHRRQVFTPEFLQGYADELQMLVQQYADDKEKVALLKALWQYADEIVEHHHH
HH

Ligands and cofactors

ID	Name	Formula	Copies
PO4	Phosphate ion	O4 P	1
MG	Magnesium ion	Mg	1

Water and common crystallization additives (GOL) are not listed.

Primary citation

Structure of Escherichia coli exonuclease I suggests how processivity is achieved. Breyer, W.A., Matthews, B.W. Nat Struct Biol (2000) 7:1125-1128. DOI 10.1038/81978 · PubMed

Other PDB entries of the same protein (UniProt P04995 (AlphaFold model), which also has an AlphaFold model), best resolution first:

2QXF 1.5 Å, Product bound structure of exonuclease I at 1.5 angstrom resolution
3HL8 1.55 Å, Crystal structure of exonuclease I in complex with inhibitor BCBP
3HP9 1.6 Å, Crystal structure of SSB/Exonuclease I in complex with inhibitor CFAM
3C95 1.7 Å, Exonuclease I (apo)
4JRP 1.95 Å, Structure of E. coli Exonuclease I in complex with a 5cy-dT13 oligonucleotide
4HCB 2.0 Å, The metal-free form of crystal structure of E.coli ExoI-ssDNA complex
3C94 2.7 Å, ExoI/SSB-Ct complex
4HCC 2.96 Å, The zinc ion bound form of crystal structure of E.coli ExoI-ssDNA complex
4JRQ 3.0 Å, Crystal structure of E. coli Exonuclease I in complex with a 5cy-dA13 oligonucleotide
4JS4 3.1 Å, Crystal structure of E. coli Exonuclease I in complex with a dA16 oligonucleotide
4JS5 3.5 Å, Crystal structure of E. coli Exonuclease I in complex with a dT13 oligonucleotide

Browse structure collections

About this viewer

MolViewer shows 1FXX directly in your browser with nothing to install. Switch between cartoon, ball-and-stick, spacefill and surface views, color by chain, secondary structure or B-factor, measure distances, angles and dihedrals, and share or embed the view.