Amino acid residues in the GIY-YIG endonuclease II of phage T4 affecting sequence recognition and binding as well as catalysis.

ABSTRACT: Phage T4 endonuclease II (EndoII), a GIY-YIG endonuclease lacking a carboxy-terminal DNA-binding domain, was subjected to site-directed mutagenesis to investigate roles of individual amino acids in substrate recognition, binding, and catalysis. The structure of EndoII was modeled on that of UvrC. We found catalytic roles for residues in the putative catalytic surface (G49, R57, E118, and N130) similar to those described for I-TevI and UvrC; in addition, these residues were found to be important for substrate recognition and binding. The conserved glycine (G49) and arginine (R57) were essential for normal sequence recognition. Our results are in agreement with a role for these residues in forming the DNA-binding surface and exposing the substrate scissile bond at the active site. The conser

SUBMITTER: Lagerback P 

PROVIDER: S-EPMC2519379 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature