1.S.2.3.2
The BMC-H or CutR: BMC shell protein of 116 aas. Sutter et al. 2019 have engineered a synthetic protein that consists of a tandem duplication of BMC-H connected by a short linker. The synthetic protein forms cyclic trimers that self-assemble to form a smaller (25 nm) icosahedral shell with gaps at the pentamer positions. When coexpressed in vivo with the pentamer fused to an affinity tag, complete icosahedral shells could be purified (Sutter et al. 2019). It is a minor shell protein of the choline degradation-specific bacterial microcompartment (BMC). Proteins such as this one with circularly permuted BMC domains may play a key role in conferring heterogeneity and flexibility in this BMC.