TY - JOUR
T1 - Expression, purification and characterization of α-synuclein fibrillar specific scFv from inclusion bodies
AU - Gupta, Vijay
AU - Sudhakaran, Indulekha P.
AU - Islam, Zeyaul
AU - Vaikath, Nishant N.
AU - Hmila, Issam
AU - Lukacsovich, Tamas
AU - Kolatkar, Prasanna R.
AU - El-Agnaf, Omar M.A.
N1 - Publisher Copyright:
© 2020 Gupta et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2020/11
Y1 - 2020/11
N2 - Aggregation of α-synuclein (α-syn) has been implicated in multiple neurodegenerative disorders including Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), collectively grouped as synucleinopathies. Recently, recombinant antibody fragments (Fab, scFvs and diabodies) against α-syn have emerged as an alternative to the traditional full-length antibody in immunotherapeutic approaches owing to their advantages including smaller size and higher stability, specificity and affinity. However, most of the recombinant antibody fragments tend to be expressed as inclusion bodies (IBs) making its purification extremely challenging. In the current study, a single-chain variable fragment (scFv-F) antibody, targeting the pathogenic α-syn fibrils, was engineered and expressed in E. coli. Majority of the expressed scFv-F accumulated in insoluble aggregates as IBs. A variety of mild and harsh solubilizing conditions were tested to solubilize IBs containing scFv-F to obtain the active protein. To preserve secondary structure and bioactivity, a mild solubilizing protocol involving 100mM Tris, pH 12.5 with 2Murea was chosen to dissolve IBs. Slow on-column refolding method was employed to subsequently remove urea and obtain active scFv-F. A three-dimensional (3D) model was built using homology modeling and subjected to molecular docking with the known α-syn structure. Structural alignment was performed to delineate the potential binding pocket. The scFv-F thus purified demonstrated high specificity towards α-syn fibrils compared to monomers. Molecular modeling studies suggest that scFv-F shares the same structural topology with other known scFvs. We present evidence through structural docking and alignment that scFv-F binds to α-syn C-terminal region. In conclusion, mild solubilization followed by slow oncolumn refolding can be utilized as a generalized and efficient method for hard to purify disease relevant insoluble proteins and/or antibody molecules from IBs.
AB - Aggregation of α-synuclein (α-syn) has been implicated in multiple neurodegenerative disorders including Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA), collectively grouped as synucleinopathies. Recently, recombinant antibody fragments (Fab, scFvs and diabodies) against α-syn have emerged as an alternative to the traditional full-length antibody in immunotherapeutic approaches owing to their advantages including smaller size and higher stability, specificity and affinity. However, most of the recombinant antibody fragments tend to be expressed as inclusion bodies (IBs) making its purification extremely challenging. In the current study, a single-chain variable fragment (scFv-F) antibody, targeting the pathogenic α-syn fibrils, was engineered and expressed in E. coli. Majority of the expressed scFv-F accumulated in insoluble aggregates as IBs. A variety of mild and harsh solubilizing conditions were tested to solubilize IBs containing scFv-F to obtain the active protein. To preserve secondary structure and bioactivity, a mild solubilizing protocol involving 100mM Tris, pH 12.5 with 2Murea was chosen to dissolve IBs. Slow on-column refolding method was employed to subsequently remove urea and obtain active scFv-F. A three-dimensional (3D) model was built using homology modeling and subjected to molecular docking with the known α-syn structure. Structural alignment was performed to delineate the potential binding pocket. The scFv-F thus purified demonstrated high specificity towards α-syn fibrils compared to monomers. Molecular modeling studies suggest that scFv-F shares the same structural topology with other known scFvs. We present evidence through structural docking and alignment that scFv-F binds to α-syn C-terminal region. In conclusion, mild solubilization followed by slow oncolumn refolding can be utilized as a generalized and efficient method for hard to purify disease relevant insoluble proteins and/or antibody molecules from IBs.
UR - http://www.scopus.com/inward/record.url?scp=85095802772&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0241773
DO - 10.1371/journal.pone.0241773
M3 - Article
C2 - 33156828
AN - SCOPUS:85095802772
SN - 1932-6203
VL - 15
JO - PLoS ONE
JF - PLoS ONE
IS - 11 November
M1 - e0241773
ER -