Recognition of 2'-hydroxyl groups by Escherichia coli ribonuclease HI.
In order to investigate the hydrogen-bonding interactions between Escherichia coli ribonuclease HI and the 2'-hydroxyl functions of the substrate, oligonucleotide duplexes containing 2'-amino-2'-deoxyuridine or 2'-fluoro-2'-deoxyuridine at a specific site were used, and their affinities for the enzyme were determined by kinetic analyses. The results indicate that the hydroxyl groups of the nucleoside 3'-adjacent to the cleaved phosphodiester linkage and the second nucleoside 5' to the cleaved phosphodiester act as both a proton donor and an acceptor and as a proton acceptor, respectively, in the enzyme-substrate complex. A molecular model was constructed using the interactions derived from the results.
Iwai
S
S
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Kataoka
S
S
Wakasa
M
M
Ohtsuka
E
E
Nakamura
H
H
D001483:Base Sequence; D003857:Deoxyuridine / Q000031:analogs & derivatives; D004926:Escherichia coli / Q000201:enzymology*; D005467:Floxuridine / Q000378:metabolism; D006860:Hydrogen Bonding; D017665:Hydroxyl Radical / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016914:Ribonuclease H / Q000737:chemistry / Q000378:metabolism*; D012263:Ribonucleosides
D009841:Oligonucleotides; D012263:Ribonucleosides; D005467:Floxuridine; D017665:Hydroxyl Radical; C037289:2'fluoro-2'-deoxyuridine; D016914:Ribonuclease H; C078856:ribonuclease HI; D003857:Deoxyuridine