Table 2.

Restriction enzymes used for identification of methylation sites on chromosomal DNA of Synechocystisa

Restriction enzymeRecognition sequencebCleavage of chromo- somal DNAFrequency (in bp) of occurrence in:
Chromoso- mal DNAcRandom sequence
PvuId  C G A T C GNoe1/6981/4,096
SgfIG C G A T CG CNoe1/1,1311/65,536
ApaI  G G G CC CNo1/3,7381/4,096
EaeI(C/T)G G CC(G/A)No1/5441/2,048
HaeIII    G G C CNoe1/1861/256
DpnI    G A T CYese1/2391/256
MboI    G A T CNoe1/2391/256
Sau3AI    G A T CYese1/2391/256
  • a The following enzymes were additionally tested and found able to cut Synechocystis DNA:AflII, AflIII, AhaII, AluI,Asp718I, AspEI, AvaI,AvaII, BamHI, BglII,BstNI, CelII, ClaI,DdeI, DpnI, Eco47I,Eco47III, EcoRI, EcoRII,EcoRV, EspI, Fnu4HI,HindIII, HpaI, HpaII,MvaI, NcoI, PstI,PvuII, SacI, SmaI,XbaI, and XhoI. For enzymes in boldface, see footnote e.

  • b Underlining indicates that methylation inhibited restriction (24). Boldfacing indicates that N6-methyladenine is a prerequisite for restriction (24). Italicizing indicates that restriction is not influenced by methylation (24).

  • c Based on the sequence of the entire genome ofSynechocystis (11).

  • d Methylation of the first cytosine probably inhibited restriction (see Results).

  • e Restriction was controlled additionally to gel electrophoresis by Southern hybridization experiments.