拟南芥 BAH1 与大肠杆菌热胁迫耐受的关系分析
Functional analysis of Arabidopsis thaliana BAH1 in

泛素化是生物体内重要的蛋白修饰途径，E3泛素连接酶具有底物蛋白的特异识别功能。拟南芥BAH1含有保守的C3H4型RING结构域，能结合两个锌离子形成交叉式锌指结构，与DnaJ锌指结构类似。通过体外泛素化实验证明BAH1具有E3连接酶活性。在大肠杆菌（E. coli）中的热敏感表型弥补实验发现BAH1具有DnaJ锌指结构类似的功能。因此，BAH1在E. coli中的功能有可能与DnaJ相似，通过锌指结构参与DnaK/DnaJ伴侣系统发挥功能。
Protein ubiquitination is one classic type of post-translational modification. The ubiquitin ligase E3 could interact directly with the substrate and mediate in large part the ubiquitination specificity. Arabidopsis thaliana BAH1 encodes a ubiquitin E3 ligase with a C3HC4-RING finger domain, which could bind two zinc ions to form a cross brace zinc finger. Here, we found the zinc finger structure of BAH1 and DnaJ was similar. Further self-ubiquitination assay in vitro demonstrated BAH1 possessed E3 ligase activity. We also found BAH1 can confer heat tolerance of E. coli as DnaJ by temperature-sensitive assays. Hence, these results indicated that BAH1 may improve heat tolerance of E. coli through interacting with DnaK/DnaJ chaperone system