biostudies-literatureYoung EJNational Institute of Allergy and Infectious DiseasesNIAID NIH HHSBasic Energy Sciences1405-1413https://www.ebi.ac.uk/biostudies/studies/S-EPMC12090211biostudies-literatureUnknown14(5)Naturally evolved and synthetically designed forms of compartmentalization benefit encapsulated function by increasing local concentrations of substrates and protecting cargo from destabilizing environments and inhibitors. Crucial to understanding the fundamental principles of compartmentalization are experimental systems enabling the measurement of the permeability rates of small molecules. Here, we report the experimental measurement of the small-molecule permeability of a 40 nm icosahedral bacterial microcompartment shell. This was accomplished by heterologous loading of light-producing luciferase enzymes and kinetic measurement of luminescence using stopped-flow spectrophotometry. Compared to free enzyme, the luminescence signal kinetics was slower when the luciferase was encapsulated ACS synthetic biologyQuantitative Measurement of Molecular Permeability to a Synthetic Bacterial Microcompartment Shell System.PMC12090211R01 AI114975DE-SC00233955R01AI114975-08Kirst HKerfeld CADwyer MEVermaas JVYoung EJfalseQuantitative Measurement of Molecular Permeability to a Synthetic Bacterial Microcompartment Shell System.Naturally evolved and synthetically designed forms of compartmentalization benefit encapsulated function by increasing local concentrations of substrates and protecting cargo from destabilizing environments and inhibitors. Crucial to understanding the fundamental principles of compartmentalization are experimental systems enabling the measurement of the permeability rates of small molecules. Here, we report the experimental measurement of the small-molecule permeability of a 40 nm icosahedral bacterial microcompartment shell. This was accomplished by heterologous loading of light-producing luciferase enzymes and kinetic measurement of luminescence using stopped-flow spectrophotometry. Compared to free enzyme, the luminescence signal kinetics was slower when the luciferase was encapsulated 2025-01-01T00:00:00Z2025 May2026-06-01T07:54:17.827Z2026-04-08T10:46:46.534ZS-EPMC120902113980873510.1021/acssynbio.4c00290