Open AccessRecognition site of Escherichia coli B restriction enzyme on ϕXsB1 and simian virus 40 DNAs: An interrupted sequence
Author(s) -
James A. Lautenberger,
Nancy C. Kan,
David Lackey,
Stuart Linn,
Marshall H. Edgell,
Clyde A. Hutchison
Publication year - 1978
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.75.5.2271
Subject(s) - restriction enzyme , biology , escherichia coli , dna , microbiology and biotechnology , restriction fragment , nucleic acid sequence , restriction site , restriction map , base pair , genetics , virology , gene
Methyl groups placed on ϕXsB1 replicative form DNA by theEscherichia coli B modification enzyme are located in the overlap between fragmentsMbo II-3 andAlu I-2, a 61-base-pair DNA segment. Mutations that led to loss of susceptibility to restriction byE. coli B occurred within this segment at three positions spanning 14 nucleotides. A sequence difference between ϕXsB1 and ϕXam 3cs 70, a ϕX174 strain not restricted byE. coli B, occurs at one of these positions. The site on simian virus 40 DNA methylated by the modification enzyme is located in the 115-base-pair overlap between fragmentsHae III-I andAlu I-G. The sequences of these segments of ϕXsB1 and simian virus 40 DNA and two regions of phage f1 DNA recognized by theE. coli B restriction enzyme [Ravetch, J. V., Horiuchi, K. & Zinder, N. D. (1978)Proc. Natl. Acad. Sci. USA 75, 2266-2270] contain a homology of nine bases in the configuration:5′-T-G-A... 8N... T-G-C-T... 9N... T-N-N-T-3′. The sequence 5′-T-G-A... 8N... T-G-C-T-3′ may constitute the restriction enzyme recognition site since it does not occur in ϕXam 3cs 70 DNA and occurs only once in simian virus 40 DNA, and since all observed mutations leading to loss of the site occur at one of the bases specified by this sequence. Analysis of the sequence of ϕXam 3cs 70 showed that if no other residues are recognized, all seven of these bases are essential for recognition and the interval between the two groups of specified bases must be precisely eight.