RecA protein promotes strand exchange with DNA substrates containing isoguanine and 5-methyl isocytosine.
Biochemistry
; 39(33): 10177-88, 2000 Aug 22.
Article
in En
| MEDLINE
| ID: mdl-10956007
ABSTRACT
The Escherichia coli RecA protein pairs homologous DNA molecules and promotes DNA strand exchange in vitro. We have examined DNA strand exchange between a 70 nucleotide ssDNA fragment and a 40 bp duplex, in which all G and C residues (at 18 positions distributed throughout the 40 bp exchanged region) were replaced with the nonstandard nucleosides 2'-deoxyisoguanosine (iG) and 2'-deoxy-5-methylisocytidine (MiC), respectively. We demonstrate that the nonstandard oligonucleotides are substrates for the RecA protein, permitting DNA strand exchange in vitro at a rate and efficiency comparable to exchange with normal DNA substrates. This observation provides an expanded experimental basis for discussions of potential roles for iG and MiC in a genetic code. Experiments of this type also provide another avenue for exploring RecA-facilitated DNA pairing mechanisms.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rec A Recombinases
/
Recombination, Genetic
/
DNA
/
Cytosine
/
DNA-Binding Proteins
/
Guanine
Language:
En
Journal:
Biochemistry
Year:
2000
Document type:
Article
Affiliation country:
Estados Unidos