  The implementation of natural and artificial proteins with designer
properties and functionalities offers unparalleled opportunity for functional
nanoarchitectures formed through self-assembly. However, to exploit the
opportunities offered we require the ability to control protein assembly into
the desired architecture while avoiding denaturation and therefore retaining
protein functionality. Here we address this challenge with a model system of
fluorescent proteins. Using techniques of self-assembly manipulation inspired
by soft matter where interactions between components are controlled to yield
the desired structure, we show that it is possible to assemble networks of
proteins of one species which we can decorate with another, whose coverage we
can tune. Consequently, the interfaces between domains of each component can
also be tuned, with applications for example in energy transfer. Our model
system of fluorescent proteins eGFP and mCherry retain their fluorescence
throughout the assembly process, thus demonstrating that functionality is
preserved.
