Topology effects on protein–polymer block copolymer self-assembly
Bioconjugates made of the model red fluorescent protein mCherry and synthetic polymer blocks show that topology, i.e. the BA, BA2, ABA and ABC chain structure of the block copolymers, where B represents the protein and A and C represent polymers, has a significant effect on ordering transitions an...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Royal Society of Chemistry, The
2019
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| Online Access: | http://hdl.handle.net/1721.1/120749 https://orcid.org/0000-0002-7272-7140 |
| Summary: | Bioconjugates made of the model red fluorescent protein mCherry and synthetic polymer blocks show
that topology, i.e. the BA, BA2, ABA and ABC chain structure of the block copolymers, where B represents
the protein and A and C represent polymers, has a significant effect on ordering transitions and the type
and size of nanostructures formed during microphase separation. ABA and ABC type block copolymers
were synthesized by using two site-specific bioconjugation reactions: the thiol–ene reaction with a
cysteine on mCherry and maleimide functionalized polymers, and the sortase A ligation reaction with an
LPETG sequence at the C-terminus on mCherry and a triglycine functionalized polymer. The phase behaviors of mCherry–poly(N-isopropylacrylamide) (PNIPAM) and mCherry–(PNIPAM)2 show that the shapes
of the phase diagrams are similar overall, but mCherry–(PNIPAM)2, i.e. BA2 type, yields a narrower domain
spacing than mCherry–PNIPAM, i.e. BA type. PNIPAM–mCherry–PNIPAM (ABA type) shows only lamellar
phases in the range of conditions under which ordered structures appear. PDMAPS–mCherry–PNIPAM
(ABC type) shows an ordered structure across the widest range of conditions in the four bioconjugates
and also the widest range of different nanodomain structures. The phase behavior of the ABC type implies
that the repulsive interaction between two water-soluble coil polymers can be a key factor in enhancing
the self-assembly of globular protein–polymer block copolymers. |
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