Two of A Kind: BamHI and BglII

Abstract

Among the more than 3500 Type II restriction endonucleases (REases) identified to date (Roberts et al. 2003), fourteen have been structurally characterized so far, including EcoRI (McClarin et al. 1986; Kim et al. 1990), EcoRV (Winkler et al. 1993; Kostrewa and Winkler 1995; Perona and Martin 1997; Horton and Perona 1998; Thomas et al. 1999), BamHI (Newman et al. 1994a, 1995; Viadiu and Aggarwal 1998, 2000) PvuII (Athanasiadis et al. 1994; Cheng et al.1994; Horton and Cheng 2000) FokI (Wah et al.1997, 1998), Cfrl0I (Bozic et al. 1996), BglI (Newman et al. 1998), BglII (Lukacs et al. 2000, 2001), BsoBI (van der Woerd et al. 2001), NaeI (Huai et al. 2000, 2001), NgoMIV (Deibert et al. 2000), Bse634I (an isoschizomer of Cfr10I), (Grazulis et al. 2002), MunI (Deibert et al. 1999), and HincII (Horton et al. 2002). All except Cfrl0I and Bse634I have been found to be bound to their cognate DNA sites. Despite the lack of sequence homology, all REases consist of a central β-sheet that is flanked by α-helices on both sides. Interestingly, a similar α/β core is also present in other DNA-acting enzymes such as γ-exonuclease (Kovall and Matthews 1997, 1998), MutH (Ban and Yang 1998), Vsr endonuclease (Tsutakawa et al. 1999a, b), and TnsA (Hickman et al. 2000) from the Tn7 trans-posase. In the common core only three p-strands are absolutely conserved, two of these strands contain the amino acid residues directly involved in catalysis.