First Insights on Organic Cosolvent Effects on FhuA Wildtype and FhuA Δ1-159

International Journal of Molecular Sciences

Stefanie-Joana Tenne¹ 

[1] Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringer Weg 1, Aachen, D-52074, Germany; E-Mail

关键词: secondary structure;    circular dichroism;    membrane protein;    organic cosolvent;    β-barrel;    FhuA;    precipitation;    structural integrity;   

DOI  :  10.3390/ijms13022459

来源: mdpi

【 摘 要 】

Circular dichroism (CD) and deconvolution were used to study the structural integrity of a “plugged” and an “open” FhuA transmembrane channel protein in the presence of varied concentrations of tetrahydrofuran (THF), ethanol (EtOH) and chloroform/methanol (C/M). FhuA is an Escherichia coli outer membrane protein (78.9 kDa) consisting of 22 β-sheets and an internal globular cork domain which acts as an iron transporter. FhuA and the deletion variant FhuA Δ1-159 showed comparable and remarkable resistance in the presence of THF (≤40 vol%) and EtOH (≤10 vol%). In C/M, significant differences in structural resistance were observed (FhuA stable ≤10 vol%; FhuA Δ1-159 ≤1 vol%). Deconvolution of CD-spectra for FhuA and FhuA Δ1-159 yielded β-sheet contents of 61 % (FhuA) and 58% (FhuA Δ1-159). Interestingly, FhuA and FhuA Δ1-159 had comparable β-sheet contents in the presence and absence of all three organic cosolvents. Additionally, precipitated FhuA and FhuA Δ1-159 (in 40 vol% C/M or 65 vol% THF) redissolved by supplementing the detergent n-octyl-oligo-oxyethylene (oPOE).

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.