Annealing of complementary DNA strands above the melting point of the duplex promoted by an archaeal protein

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• 作者：Guagliardi ; Annamaria ; Napoli ; Alessandra ; Rossi ; Mosé ; Ciaramella ; Maria
• 关键词：DNA annealing ; Archaea ; thermophiles ; DNA binding protein ; homologous pairing ; ds ; double-stranded ; ss ; single-stranded ; t_m ; melting point
• 刊名：Journal of Molecular Biology
• 出版年：1997
• 出版时间：April 11, 1997
• 年：1997
• 卷：267
• 期：4
• 页码：841-848
• 全文大小：293 K

文摘

One enigma in the biology of hyperthermophilic microorganisms, living near or above 100°C, is how their genomes can be stable and, at the same time, plastic at temperatures above the melting point. The non-specific DNA-binding protein Sso7d of the hyperthermophilic archaeon Sulfolobus solfataricus is known to protect DNA from thermal denaturation. We report here that Sso7d promotes the renaturation of complementary DNA strands at temperatures above the melting point of the duplex. This novel annealing activity is strictly homology-dependent, and even one mismatch in a stretch of 17 complementary bases severely reduces its efficiency. Since pairing of homologous single strands is a key step in all fundamental processes involving nucleic acids, such as transcription, replication, recombination, and repair, Sso7d is a candidate component of the protein machinery devoted to the coupling of DNA stability to metabolic flexibility at high temperature.