Structure of the DNA polymerase I (Klenow Fragment from Escherichia coli, PDB ID: 1KLN) colored according to conservation of amino acids. Asn675 and Leu676 are dipicted as space-filled model and indicate the insertion site of the group I intron found in the homologous Bacillus subtilis phage SPO1. For more information see Fig 4 in
Swithers KS, Senejani AG, Fournier GP, Gogarten JP (2009)
Conservation of intron and intein insertion sites: Implications for life histories of parasitic genetic elements.
BMC Evolutionary Biology 2009, 9:303 doi:10.1186/1471-2148-9-303 (Highly Accessed)