Structural elucidation of the binding and inhibitory properties of lanthanide (III) ions at the 3'-5' exonucleolytic active site of the Klenow fragment
Brautigam, C.A., Aschheim, K., Steitz, T.A.(1999) Chem Biol 6: 901-908
- PubMed: 10631518 
- DOI: https://doi.org/10.1016/s1074-5521(00)80009-5
- Primary Citation of Related Structures:  
1QSL - PubMed Abstract: 
Biochemical and biophysical experiments have shown that two catalytically essential divalent metal ions (termed 'A' and 'B') bind to the 3'-5' exonuclease active site of the Klenow fragment (KF) of Escherichia coli DNA polymerase I. X-ray crystallographic studies have established the normal positions in the KF 3'-5' exonuclease (KF exo) active site of the two cations and the single-stranded DNA substrate. Lanthanide (III) luminescence studies have demonstrated, however, that only a single europium (III) ion (Eu3+) binds to the KF exo active site. Furthermore, Eu3+ does not support catalysis by KF exo or several other two-metal-ion phosphoryl-transfer enzymes.
Organizational Affiliation: 
Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8114, USA.