Hennessy F, Cheetham M E, Dirr H W, Blatch G L
Department of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa.
Cell Stress Chaperones. 2000 Oct;5(4):347-58. doi: 10.1379/1466-1268(2000)005<0347:aotloc>2.0.co;2.
DnaJ-like proteins are defined by the presence of an approximately 73 amino acid region termed the J domain. This region bears similarity to the initial 73 amino acids of the Escherichia coli protein DnaJ. Although the structures of the J domains of E coli DnaJ and human heat shock protein 40 have been solved using nuclear magnetic resonance, no detailed analysis of the amino acid conservation among the J domains of the various DnaJ-like proteins has yet been attempted. A multiple alignment of 223 J domain sequences was performed, and the levels of amino acid conservation at each position were established. It was found that the levels of sequence conservation were particularly high in 'true' DnaJ homologues (ie, those that share full domain conservation with DnaJ) and decreased substantially in those J domains in DnaJ-like proteins that contained no additional similarity to DnaJ outside their J domain. Residues were also identified that could be important for stabilizing the J domain and for mediating the interaction with heat shock protein 70.
类DnaJ蛋白是由一个约73个氨基酸的区域（称为J结构域）的存在来定义的。该区域与大肠杆菌蛋白DnaJ的最初73个氨基酸相似。尽管已经使用核磁共振解析了大肠杆菌DnaJ和人类热休克蛋白40的J结构域的结构，但尚未尝试对各种类DnaJ蛋白的J结构域之间的氨基酸保守性进行详细分析。对223个J结构域序列进行了多序列比对，并确定了每个位置的氨基酸保守水平。结果发现，“真正的”DnaJ同源物（即那些与DnaJ共享完整结构域保守性的同源物）中的序列保守水平特别高，而在类DnaJ蛋白中那些除J结构域之外与DnaJ没有额外相似性的J结构域中，序列保守水平则大幅下降。还鉴定出了对于稳定J结构域以及介导与热休克蛋白70的相互作用可能很重要的残基。
