嗜热菌染色体蛋白Sso7d与DNA结合的晶体结构。

The crystal structure of the hyperthermophile chromosomal protein Sso7d bound to DNA.

作者信息

Gao Y G, Su S Y, Robinson H, Padmanabhan S, Lim L, McCrary B S, Edmondson S P, Shriver J W, Wang A H

机构信息

Department of Cell and Structural Biology, University of Illinois at Urbana-Champaign, Urbana 61801, USA.

出版信息

Nat Struct Biol. 1998 Sep;5(9):782-6. doi: 10.1038/1822.

DOI:10.1038/1822

PMID:9731772

Abstract

Sso7d and Sac7d are two small (approximately 7,000 Mr), but abundant, chromosomal proteins from the hyperthermophilic archaeabacteria Sulfolobus solfataricus and S. acidocaldarius respectively. These proteins have high thermal, acid and chemical stability. They bind DNA without marked sequence preference and increase the Tm of DNA by approximately 40 degrees C. Sso7d in complex with GTAATTAC and GCGT(iU)CGC + GCGAACGC was crystallized in different crystal lattices and the crystal structures were solved at high resolution. Sso7d binds in the minor groove of DNA and causes a single-step sharp kink in DNA (approximately 60 degrees) by the intercalation of the hydrophobic side chains of Val 26 and Met 29. The intercalation sites are different in the two complexes. Observations of this novel DNA binding mode in three independent crystal lattices indicate that it is not a function of crystal packing.

摘要

Sso7d和Sac7d分别是来自嗜热古细菌嗜热栖热菌和嗜酸热硫化叶菌的两种小蛋白（分子量约为7000），但含量丰富。这些蛋白质具有高热稳定性、酸稳定性和化学稳定性。它们结合DNA时没有明显的序列偏好，可使DNA的解链温度提高约40℃。Sso7d与GTAATTAC和GCGT(iU)CGC + GCGAACGC形成的复合物在不同的晶格中结晶，并以高分辨率解析了晶体结构。Sso7d结合在DNA的小沟中，通过Val 26和Met 29的疏水侧链插入使DNA产生一步急剧的弯折（约60度）。在两种复合物中插入位点不同。在三个独立晶格中对这种新型DNA结合模式的观察表明，这不是晶体堆积的作用。