BrkAutoDisplay: functional display of multiple exogenous proteins on the surface of Escherichia coli by using BrkA autotransporter.
BACKGROUND
Bacterial surface display technique enables the exogenous proteins or polypeptides displayed on the bacterial surface, while maintaining their relatively independent spatial structures and biological activities. The technique makes recombinant bacteria possess the expectant functions, subsequently, directly used for many applications. Many proteins could be used to achieve bacterial surface display, among them, autotransporter, a member of the type V secretion system of gram-negative bacteria, has been extensively studied because of its modular structure and apparent simplicity. However, autotransporter has not been widely used at present due to lack of a convenient genetic vector system. With our recently characterized autotransporter BrkA (Bordetella serum-resistance killing protein A) from Bordetella pertussis, we are aiming to develop a new autotransporter-based surface display system for potential wide application.


RESULTS
Here, we construct a bacterial surface display system named as BrkAutoDisplay, based on the structure of autotransporter BrkA. BrkAutoDisplay is a convenient system to host exogenous genes. In our test, this system is good to efficiently display various proteins on the outer membrane surface of Escherichia coli, including green fluorescent protein (GFP), various enzymes and single chain antibody. Moreover, the displayed GFP possesses green fluorescence, the enzymes CotA, EstPc and PalA exhibit catalytic activity 0.12, 6.88 and 0.32 mU (per 5.2 × 10(8) living bacteria cells) respectively, and the single chain antibody fragment (scFv) can bind with its antigen strongly. Finally, we showed that C41(DE3) is a good strain of E. coli for the successful functionality of BrkAutoDisplay.


CONCLUSIONS
We designed a new bacterial display system called as BrkAutoDisplay and displayed various exogenous proteins on E. coli surface. Our results indicate that BrkAutoDisplay system is worthy of further study for industrial applications.
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. sunfanganhui@163.com.|University of the Chinese Academy of Sciences, Beijing, 100049, China. sunfanganhui@163.com.
Fang
F
Sun
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. pangxy@moon.ibp.ac.cn.
Xiaoyun
X
Pang
Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China. xietian@cib.ac.cn.|University of the Chinese Academy of Sciences, Beijing, 100049, China. xietian@cib.ac.cn.
Tian
T
Xie
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. yujia@ibp.ac.cn.
Yujia
Y
Zhai
Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China. wanggg@cib.ac.cn.
Ganggang
G
Wang
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. feisun@ibp.ac.cn.
Fei
F
Sun
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry; D055162:Biocatalysis; D004798:Enzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005818:Genetic Engineering / Q000379:methods; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D019076:Transgenes
D001425:Bacterial Outer Membrane Proteins; C090007:BrkA protein, Bordetella pertussis; D004798:Enzymes; D008565:Membrane Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins