Abstract:
:The nucleotide sequence of the recognition site for the restriction-modification enzyme of Escherichia coli B (SB site) has been determined. The recognition site is a 15-nucleotide sequence consisting of the trimer 5'TGA3', followed by an 8-nucleotide domain of variable sequence, which in turn is followed by tetramer 5'TGCT3'. The sequence has no 2-fold rotational symmetry. Single base changes in the constant nucleotide domains result in the loss of sensitivity to both restriction and modification. Our data are also consistent with modification occurring by methylation of two adenine residues per SB site: one on the adenine of the trimer 5'TGA3' and the other on the complementary strand on the adenine complementary to the first thymine of the tetramer 5'TGCT3'. All nine independently isolated spontaneous mutants at the SB1 site of bacteriophage f1 are caused by a G-to-T transversion. Mutations at the SB2 site are caused by various single base changes.
journal_name
Proc Natl Acad Sci U S Aauthors
Ravetch JV,Horiuchi K,Zinder NDdoi
10.1073/pnas.75.5.2266subject
Has Abstractpub_date
1978-05-01 00:00:00pages
2266-70issue
5eissn
0027-8424issn
1091-6490journal_volume
75pub_type
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