Further Evidence for Binding of Three Single-Stranded DNA Molecules by the RecA Filament
Artikel i vetenskaplig tidskrift, 1995

The ability to accommodate three single-strands of DNA by each filamentous RecA-DNA complex, in the presence of the non-hydrolysable ATP analog, adenosine 5'-O-3-thiotriphosphate (ATP gamma S), was demonstrated by monitoring the fast renaturation that occurs between the complementary homopolymers, poly(dA) and poly(dT), upon sodium dodecyl sulfate (SDS)-induced dissociation of RecA, The renaturation could be followed from the linear dichroism signal of DNA, The reaction was fast and complete when SDS was added to a mixture of RecA having three nucleobases per subunit each of poly(dA) and poly(dT), while the reaction was slower and incomplete in the absence of RecA, The efficient renaturation indicates that the two DNA strands were bound close to each other, i,e,, to the same RecA filament. Similar fast renaturation was observed upon the addition of SDS to a mixture of RecA with three bases each of poly(dA), poly(dT), and a non-complementary DNA, poly(dC), even when one of the complementary DNAs was added last as the third strand, Since the dissociation of DNA from RecA is extremely slow in the presence of ATP gamma S, and thus no renaturation can occur within the RecA filaments, the results indicate that RecA can bind three single-stranded DNA molecules.

escherichia-coli

reca protein

linear dichroism spectroscopy

dna binding

genetic-recombination

coordination

complexes

protein

strand

exchange

renaturation

electron-microscopy

linear dichroism

exchange

stoichiometry

Författare

M. Takahashi

Bengt Nordén

Institutionen för fysikalisk kemi

Journal of Biochemistry

0021-924X (ISSN)

Vol. 117 5 947-951

Ämneskategorier

Biokemi och molekylärbiologi