文章基本信息

标题：Domain swapping oligomerization of thermostable c-type cytochrome in E. coli cells
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作者：Yugo Hayashi ; Masaru Yamanaka ; Satoshi Nagao 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
期号：1
DOI：10.1038/srep19334
语种：English
出版社：Springer Nature
摘要：Knowledge on domain swapping in vitro is increasing, but domain swapping may not occur regularly in vivo , and its information in cells is limited. Herein, we show that domain-swapped oligomers of a thermostable c -type cytochrome, Hydrogenobacter thermophilus cyt c ₅₅₂, are formed in E. coli which expresses cyt c ₅₅₂. The region containing the N-terminal α-helix and heme was domain-swapped between protomers in the dimer formed in E. coli . The amount of cyt c ₅₅₂ oligomers increased in E. coli as the cyt c ₅₅₂ concentration was increased, whereas that of high-order oligomers decreased in the order of decrease in protein stability, indicating that domain swapping decreases in cells when the protein stability decreases. Apo cyt c ₅₅₂ was detected in the cyt c ₅₅₂ oligomer formed in E. coli , but not in that of the A5F/M11V/Y32F/Y41E/I76V mutant. The cyt c ₅₅₂ oligomer containing its apo protein may form at the periplasm, since the apo protein detected by mass measurements did not contain the signal peptide. These results show that domain-swapped cyt c ₅₅₂ oligomers were formed in E. coli , owing to the stability of the transient oligomer containing the apo protein before heme attachment. This is an indication that exceedingly stable proteins may have disadvantages forming domain-swapped oligomers in cells.