TY  - JOUR
A1  - Garakani, Tayebeh Mirzaei
A1  - Liu, Zhanzhi
A1  - Glebe, Ulrich
A1  - Gehrmann, Julia
A1  - Lazar, Jaroslav
A1  - Mertens, Marie Anna Stephanie
A1  - Möller, Mieke
A1  - Hamzelui, Niloofar
A1  - Zhu, Leilei
A1  - Schnakenberg, Uwe
A1  - Böker, Alexander
A1  - Schwaneberg, Ulrich
T1  - In Situ Monitoring of Membrane Protein Insertion into Block Copolymer Vesicle Membranes and Their Spreading via Potential-Assisted Approach
T2  - ACS applied materials & interfaces
N2  - Synthosomes are polymer vesicles with trans membrane proteins incorporated into block copolymer membranes. They have been used for selective transport in or out of the vesicles as well as catalysis inside the compartments. However, both the insertion process of the membrane protein, forming nanopores, and the spreading of the vesicles on planar substrates to form solid-supported biomimetic membranes have been rarely studied yet. Herein, we address these two points and, first, shed light on the real-time monitoring of protein insertion via isothermal titration calorimetry. Second, the spreading process on different solid supports, namely, SiO2, glass, and gold, via different techniques like spin- and dip-coating as well as a completely new approach of potential-assisted spreading on gold surfaces was studied. While inhomogeneous layers occur via traditional methods, our proposed potential-assisted strategy to induce adsorption of positively charged vesicles by applying negative potential on the electrode leads to remarkable vesicle spreading and their further fusion to form more homogeneous planar copolymer films on gold. The polymer vesicles in our study are formed from amphiphilic copolymers poly(2-methyl oxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyl oxazoline) (PMOXA-b-PDMS-b-PMOXA). Engineered variants of the transmembrane protein ferric hydroxamate uptake protein component A (FhuA), one of the largest beta-barrel channel proteins, are used as model nanopores. The incorporation of FhuA Delta 1-160 is shown to facilitate the vesicle spreading process further. Moreover, high accessibility of cysteine inside the channel was proven by linkage of a fluorescent dye inside the engineered variant FhuA Delta CVFtev and hence preserved functionality of the channels after spreading. The porosity and functionality of the spread synthosomes on the gold plates have been examined by studying the passive ion transport response in the presence of Li+ and ClO4- ions and electrochemical impedance spectroscopy analysis. Our approach to form solid-supported biomimetic membranes via the potential-assisted strategy could be important for the development of new (bio-) sensors and membranes.
KW  - synthosomes
KW  - solid-supported biomimetic membranes
KW  - polymersome spreading
KW  - electrochemical impedance spectroscopy
KW  - FhuA
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/48479
SN  - 1944-8244
SN  - 1944-8252
VL  - 11
IS  - 32
SP  - 29276
EP  - 29289
PB  - American Chemical Society
CY  - Washington
ER  -