‘Star’ activity and complete loss of specificity of CeqI endonuclease

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Item Type:	Article
Title:	‘Star’ activity and complete loss of specificity of CeqI endonuclease
Creators Name:	Izsvak, Z. and Duda, E.
Abstract:	Restriction endonuclease CeqI, an isoschizomer of EcoRV, exhibits ‘star’ activity, a relaxation of specificity in the presence of Mn2+, dimethyl sulphoxide or glycerol. The enzyme cleaves a set of sequences that differ from the canonical GATATC by only one nucleotide in positions 2, 3, 4 or 5. Two of these sequences are not cleaved if modified by dam methylase. A further loss of specificity can be observed in circumstances less favourable for the enzyme, namely low-ionic-strength buffers of pH values below 6.0 or above 9.4. This activity seems to cleave DNA at any sequence, producing a smear instead of well-defined bands. Partial renaturation of the denatured enzyme gives rise to a similar non-specific nuclease activity.
Keywords:	Base Sequence, DNA Restriction Enzymes, Type II Site-Specific Deoxyribonucleases, Dimethyl Sulfoxide, Glycerol, Hydrogen-Ion Concentration, Manganese, Rhodococcus
Source:	Biochemical Journal
ISSN:	0264-6021
Publisher:	Portland Press
Volume:	258
Number:	1
Page Range:	301-303
Date:	February 1989
Official Publication:	https://doi.org/10.1042/bj2580301
PubMed:	View item in PubMed

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