嗜热栖热放线菌HTA426 DnaD蛋白N端结构域的晶体结构

Crystal structure of the N-terminal domain of Geobacillus kaustophilus HTA426 DnaD protein.

作者信息

Huang Cheng-Yang, Chang Yi-Wei, Chen Wei-Ti

机构信息

Department of Biomedical Sciences, Chung Shan Medical University, No. 110, Sec. 1, Chien-Kuo N. Road, Taichung 402, Taiwan.

出版信息

Biochem Biophys Res Commun. 2008 Oct 17;375(2):220-4. doi: 10.1016/j.bbrc.2008.07.160. Epub 2008 Aug 12.

DOI:10.1016/j.bbrc.2008.07.160

PMID:18703019

Abstract

The DnaD is one of the primosomal proteins that are required for initiation and re-initiation of chromosomal DNA replication in Gram-positive bacteria. The DnaD protein is composed of two major structural domains: an N-terminal oligomerization domain and a C-terminal ssDNA binding domain. Here, we report the crystal structure of the N-terminal domain (aa 1-128) of DnaD (DnaDn) of Geobacillus kaustophilus HTA426 at 2.3A resolution. The structure of DnaDn reveals an extended winged-helix fold, a typical double-stranded DNA binding motif as winged-helix proteins. DnaDn formed tetramers in the crystalline state, but the results of gel filtration chromatography further indicated that this domain of DnaD was a stable dimer in solution. The structural analysis of DnaDn may suggest the binding sites for DNA and DnaB, and an assembly mechanism for Gram-positive bacterial DNA replication primosome.

摘要

DnaD是革兰氏阳性菌染色体DNA复制起始和重新起始所需的引发体蛋白之一。DnaD蛋白由两个主要结构域组成：一个N端寡聚化结构域和一个C端单链DNA结合结构域。在此，我们报道了嗜碱地芽孢杆菌HTA426的DnaD（DnaDn）N端结构域（氨基酸1 - 128）在2.3埃分辨率下的晶体结构。DnaDn的结构揭示了一种延伸的翼状螺旋折叠，这是翼状螺旋蛋白典型的双链DNA结合基序。DnaDn在晶体状态下形成四聚体，但凝胶过滤色谱结果进一步表明，DnaD的这个结构域在溶液中是稳定的二聚体。对DnaDn的结构分析可能提示了DNA和DnaB的结合位点，以及革兰氏阳性菌DNA复制引发体的组装机制。