TAILIEUCHUNG - Báo cáo khoa học: Formation of nucleoprotein RecA filament on single-stranded DNA Analysis by stepwise increase in ligand complexity

RecA protein plays a pivotal role in homologous recombination inEscheri-chia coli. RecA polymerizes on single-stranded (ss) DNA forming a nucleo-protein filament. Then double-stranded (ds) DNA is bound and searched for segments homologous to the ssDNA. Finally, homologous strands are exchanged, a new DNA duplex is formed, and ssDNA is displaced. We report a quantitative analysis of RecA interactions with ss d(pN)n of var-ious structures and lengths using these oligonucleotides as inhibitors of RecA filamentation on d(pT)20 | iFEBS Journal Formation of nucleoprotein RecA filament on single-stranded DNA Analysis by stepwise increase in ligand complexity Irina P. Bugreeva Dmitry V. Bugreev and Georgy A. Nevinsky Institute of ChemicalBiology and FundamentalMedicine Siberian Division of Russian Academy of Sciences Novosibirsk Russia Keywords RecA DNA recognition mechanism Correspondence G. A. Nevinsky Laboratory of repair enzymes Institute of ChemicalBiology and FundamentalMedicine 8 Lavrentieva Ave. 630090 Novosibirsk Russia Fax 7 3832 333677 Tel 7 3832 396226 E-mail nevinsky@ Received 8 January 2005 revised 24 February 2005 accepted 31 March 2005 doi RecA protein plays a pivotal role in homologous recombination in Escherichia coli. RecA polymerizes on single-stranded ss DNA forming a nucleoprotein filament. Then double-stranded ds DNA is bound and searched for segments homologous to the ssDNA. Finally homologous strands are exchanged a new DNA duplex is formed and ssDNA is displaced. We report a quantitative analysis of RecA interactions with ss d pN n of various structures and lengths using these oligonucleotides as inhibitors of RecA filamentation on d pT 20. DNA recognition appears to be mediated by weak interactions between its structural elements and RecA monomers within a filament. Orthophosphate and dNMP are minimal inhibitors of RecA filamentation I50 12-20 mm . An increase in homo-d pN 2_40 length by one unit improves their affinity for RecA f factor approximately twofold through electrostatic contacts of RecA with internucleoside phosphate DNA moieties f w and specific interactions with T or C bases f w interactions with adenine bases are negligible. RecA affinity for d pN n containing normal or modified nucleobases depends on the nature of the base features of the DNA structure. The affinity considerably increases if exocyclic hydrogen bond acceptor moieties are present in the bases. We analyze possible reasons underlying

• Báo cáo khoa học
• Report medicine
• traditional medicine
• scientific reports
• breast cancer
• biological activities
• environmental medicine
• medical knowledge
• medical research
• analysis of cytoplasmic
• oxidation
• Crystal structure
• bacteria
• hemoglobin
• medicine
• cell proliferation
• chemical reaction
• gastric cancer
• hormone medicine
• tumor cells
• biochemical studies