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 heat tolerance of E.coli

拟南芥BAH1含有保守的C3H4型RING结构域,与DnaJ锌指结构类似.利用原核表达纯化的BAH1进行体外泛素化实验证明了BAH1具有E3连接酶活性.然后通过表型回复实验发现BAH1融合J-domain结构域后(JdBAH1)和DnaJ一样能明显弥补danJ突变株MF634的热敏表型,在43℃存活;而转入突变锌指结构的JdBAH1C231S,C234S,C276S,C279S(JdBAH1△Zn1/2)菌株在43℃高温条件下不能存活,说明BAH1在大肠杆菌内具有类似DnaJ锌指结构的功能.因此,BAH1在E.coli中的功能有可能与DnaJ相似,通过锌指结构参与了DnaK/DnaJ伴侣系统发挥功能.

Arabidopsis thaliana BAH1 has a C3HCA-RING finger domain, which is similar to the zinc finger structure of DnaJ. Further self-ubiquitination assay in vitrousing purified BAH1 demonstrated BAH1 possessed E3 ligase activity. Then a phenotypic recovery experiment which showed JdBAH1 （containing BAH1 and J-do- main） was performed, the same with DnaJ, significantly compensated for the thermal phenotype of danJ mutant strain MF634. As a result, both could survive at 43~C o However, the strain which was imported the mutated zinc finger structure JdBAH1C231S, C234S, C276S, C279S（JdBAH1 AZnl/2） was not able to survive at 43℃. Hence, these results indicated that BAH1 may improve heat tolerance of E. coli through interacting with DnaK/ DnaJ chaperone system. These results indicated that BAH1 may improve heat tolerance of E. coli through inter- acting with DnaK/DnaJ chaperone system.