The dimer-dimer interaction surface of the replication terminator protein of Bacillus subtilis and termination of DNA replication.
AUTOR(ES)
Manna, A C
RESUMO
The replication terminator protein (RTP) of Bacillus subtilis causes polar fork arrest at replication termini by sequence-specific interaction of two dimeric proteins with the terminus sequence. The crystal structure of the RTP protein has been solved, and the structure has already provide valuable clues regarding the structural basis of its function. However, it provides little information as to the surface of the protein involved in dimer-dimer interaction. Using site-directed mutagenesis, we have identified three sites on the protein that appear to mediate the dimer-dimer interaction. Crystallographic analysis of one of the mutant proteins (Y88F) showed that its structure is unaltered when compared to the wild-type protein. The locations of the three sites suggested a model for the dimer-dimer interaction that involves an association between two beta-ribbon motifs. This model is supported by a fourth mutation that was predicted to disrupt the interaction and was shown to do so. Biochemical analyses of these mutants provide compelling evidence that cooperative protein-protein interaction between two dimers of RTP is essential to impose polar blocks to the elongation of both DNA and RNA chains.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=39592Documentos Relacionados
- Defective spectrin dimer-dimer association with hereditary elliptocytosis.
- Termination of DNA replication in vitro: requirement for stereospecific interaction between two dimers of the replication terminator protein of Bacillus subtilis and with the terminator site to elicit polar contrahelicase and fork impedance.
- Altered spectrin dimer-dimer association and instability of erythrocyte membrane skeletons in hereditary pyropoikilocytosis.
- A new isoleucine substitution of Val-20 in transthyretin tetramers selectively impairs dimer-dimer contacts and causes systemic amyloidosis.
- The structure and function of the replication terminator protein of Bacillus subtilis: identification of the 'winged helix' DNA-binding domain.