Recent structural insights into bacterial microcompartment shells

Bacterial microcompartments are organelle-like structures that enhance a variety of metabolic functions in diverse bacteria. Composed entirely of proteins, thousands of homologous hexameric shell proteins tesselate to form facets while pentameric proteins form the vertices of a polyhedral shell that encapsulates various enzymes, substrates and cofactors. Recent structural data have highlighted nuanced variations in the sequence and topology of microcompartment shell proteins, emphasizing how variation and specialization enable the construction of complex molecular machines. Recent studies engineering synthetic miniaturized microcompartment shells provide additional frameworks for dissecting principles of microcompartment structure and assembly. This review updates our current understanding of bacterial microcompartment shell proteins, providing new insights and highlighting outstanding questions.