Terakawa Tsuyoshi, Bisht Shveta, Eeftens Jorine M, Dekker Cees, Haering Christian H, Greene Eric C
Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
Cell Biology and Biophysics Unit, Structural and Computational Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
Science. 2017 Nov 3;358(6363):672-676. doi: 10.1126/science.aan6516. Epub 2017 Sep 7.
Condensin plays crucial roles in chromosome organization and compaction, but the mechanistic basis for its functions remains obscure. We used single-molecule imaging to demonstrate that condensin is a molecular motor capable of adenosine triphosphate hydrolysis-dependent translocation along double-stranded DNA. Condensin's translocation activity is rapid and highly processive, with individual complexes traveling an average distance of ≥10 kilobases at a velocity of ~60 base pairs per second. Our results suggest that condensin may take steps comparable in length to its ~50-nanometer coiled-coil subunits, indicative of a translocation mechanism that is distinct from any reported for a DNA motor protein. The finding that condensin is a mechanochemical motor has important implications for understanding the mechanisms of chromosome organization and condensation.
凝聚素在染色体组织和压缩过程中发挥着关键作用,但其功能的机制基础仍不清楚。我们利用单分子成像技术证明,凝聚素是一种分子马达,能够沿着双链DNA进行依赖三磷酸腺苷水解的易位。凝聚素的易位活性快速且高度持续,单个复合物以约每秒60个碱基对的速度平均移动≥10千碱基的距离。我们的结果表明,凝聚素的移动步长可能与其约50纳米的卷曲螺旋亚基长度相当,这表明其易位机制不同于任何已报道的DNA马达蛋白。凝聚素是一种机械化学马达这一发现对于理解染色体组织和凝聚机制具有重要意义。