Structure of a Minimal α-Carboxysome-Derived Shell and Its Utility in Enzyme Stabilization
Yong Quan Tan, Samson Ali, Bo Xue, Wei Zhe Teo, Lay Hiang Ling, Maybelle Kho Go, Hong Lv, Robert Robinson, Akihiro Narita, Wen Shan Yew
Abstract
α-carboxysome, which we term Cso-shell. Using cryogenic electron microscopy, the atomic-level structures of two shell forms were obtained, reinforcing notions of evolutionarily conserved features in bacterial microcompartment shell architecture. Encapsulation peptide sequences that facilitate loading of heterologous protein cargo within the shells were identified. We further provide a first demonstration in utilizing minimal bacterial microcompartment-derived shells for hosting heterologous enzymes. Cso-shells were found to stabilize enzymatic activities against heat shock, presence of methanol co-solvent, consecutive freeze-thawing, and alkaline environments. This study yields insights into α-carboxysome assembly and advances the utility of synthetic bacterial microcompartments as nanoreactors capable of stabilizing enzymes with varied properties and reaction chemistries.