Endonuclease II (deoxyribonucleate oligonucleotidohydrolase, EC 3.1.4.30) of Escherichia coli has been shown to break phosphodiester bonds in alkylated DNA and depurinated DNA. The hypothesis that depurination is a step in the mechanism of the reaction with alkylated DNA is supported by in vitro experiments with DNA reacted with N-methyl-N-nitrosourea. Endonuclease II releases O(6)-methylguanin...

UNLABELLED Restriction endonucleases are indispensable tools in molecular biology and biotechnology. Type II restriction endonucleases are part of restriction modification systems. DNA fragment extraction and restriction mapping are the basis for several biotechnological activities. WebFARM is a server application for identifying restriction endonuclease recognition sites and to give informatio...

Specific restriction endonucleases were detected in three serotypes of Salmonella spp. isolated from humans in Japan from 1970 to 1987: an isoschizomer of AvaII endonuclease at a frequency of 0.91 in Salmonella infantis, an isoschizomer of KpnI at a frequency of 0.34 in Salmonella thompson, and an isoschizomer of StyI at a frequency of 0.30 in Salmonella blockley. Of interest is that restrictio...

In most eukaryotes, genes encoding ribosomal RNAs (rDNA) are clustered in long tandem head-to-tail repeats. Studies of Saccharomyces cerevisiae have indicated that rDNA copy number is maintained through recombination events associated with site-specific blockage of replication forks (RFs). Here, we describe two Schizosaccharomyces pombe proteins, homologs of S. cerevisiae Slx1 and Slx4, as subu...

Ho endonuclease of Saccharomyces cerevisiae is a homing endonuclease that makes a site-specific double-strand break in the MAT gene in late G(1). Here we show that Ho is rapidly degraded via the ubiquitin-26S proteasome system through two ubiquitin-conjugating enzymes UBC2(Rad6) and UBC3(Cdc34). UBC2(Rad6) is complexed with the ring finger DNA-binding protein Rad18, and we find that Ho is stabi...

The Mus81 endonuclease resolves recombination intermediates and mediates cellular responses to exogenous replicative stress. Here, we show that Mus81 also regulates the rate of DNA replication during normal growth by promoting replication fork progression while reducing the frequency of replication initiation events. In the absence of Mus81 endonuclease activity, DNA synthesis is slowed and rep...

BalI, a type II restriction-modification (R-M) system from the bacterium, Brevibacterium albidum, recognizes the DNA sequence 5'-TGGCCA-3'. We cloned the genes encoding the BalI restriction endonuclease and methyltransferase and expressed them in Escherichia coli. The two genes were aligned tail-to-tail and their termination codons overlapped. BalI restriction endonuclease and methyltransferase...

Restriction endonucleases and other nucleic acid cleaving enzymes form a large and extremely diverse superfamily that display little sequence similarity despite retaining a common core fold responsible for cleavage. The lack of significant sequence similarity between protein families makes homology inference a challenging task and hinders new family identification with traditional sequence-base...