2QXF

Structure of Escherichia coli exonuclease I in complex with thymidine 5'-monophosphate.

(2008) Acta Crystallogr D Biol Crystallogr 64: 206-210

• PubMed: 18219121 Search on PubMed
• DOI: https://doi.org/10.1107/S090744490706012X
• Primary Citation of Related Structures:  
  2QXF


• PubMed Abstract: 
  

  In Escherichia coli, exonuclease I (ExoI) is a monomeric processive 3'-5' exonuclease that degrades single-stranded DNA. The enzyme has been implicated as primarily being involved in repairing frameshift mutations. The structure of the enzyme has previously been determined in a hexagonal space group at 2.4 A resolution. Here, the structure of ExoI in complex with a nucleotide product, thymidine 5'-monophosphate, is described in an orthorhombic space group at 1.5 A resolution. This new high-resolution structure provides some insight into the interactions involved in binding a nucleotide product. The conserved active site contains a unique metal-binding position when compared with orthologous sites in the Klenow fragment, T4 DNA polymerase and dnaQ. This unique difference is proposed to be a consequence of the repositioning of an important histidine, His181, away from the active site.

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Organizational Affiliation: 

Institute of Molecular Biology, Howard Hughes Medical Institute and Department of Physics, 1229 University of Oregon, Eugene, OR 97403-1229, USA. robert.busam@ki.se