Comparison of the nucleotide and amino acid sequences of the RsrI and EcoRI restriction endonucleases.
The RsrI endonuclease, a type-II restriction endonuclease (ENase) found in Rhodobacter sphaeroides, is an isoschizomer of the EcoRI ENase. A clone containing an 11-kb BamHI fragment was isolated from an R. sphaeroides genomic DNA library by hybridization with synthetic oligodeoxyribonucleotide probes based on the N-terminal amino acid (aa) sequence of RsrI. Extracts of E. coli containing a subclone of the 11-kb fragment display RsrI activity. Nucleotide sequence analysis reveals an 831-bp open reading frame encoding a polypeptide of 277 aa. A 50% identity exists within a 266-aa overlap between the deduced aa sequences of RsrI and EcoRI. Regions of 75-100% aa sequence identity correspond to key structural and functional regions of EcoRI. The type-II ENases have many common properties, and a common origin might have been expected. Nevertheless, this is the first demonstration of aa sequence similarity between ENases produced by different organisms.
Stephenson
F H
FH
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0554.
Ballard
B T
BT
Boyer
H W
HW
Rosenberg
J M
JM
Greene
P J
PJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D015246:Deoxyribonuclease EcoRI / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010957:Plasmids; D012242:Rhodobacter sphaeroides / Q000201:enzymology / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000235:genetics*
D003062:Codon; D015345:Oligonucleotide Probes; C020098:DNA modification methylase EcoRI; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D015246:Deoxyribonuclease EcoRI