A component of the bacterial microcompartment (BMC) shell dedicated to ethanolamine degradation (Probable). Two crystal forms have been seen; a form with a closed central pore that has 3 very small (1.1-2.2 Angstroms) channels per trimer lined by acidic and aromatic residues (PubMed:19451619, PubMed:20044574). A form with a large central pore (8-12 Angstroms) has also been seen; this is probably a functional pore which allows molecules to enter and exit the BMC in a selective, gated manner (PubMed:20851901, PubMed:20044574). Another group only sees the central pore in the presence of Zn(2+); soaking crystals in ZnCl(2) leads to dramatic conformational changes that open a central pore of about 12 Angstroms. Whether Zn(2+) binding is physiologically relevant is unclear, however it suggests a gating mechanism exists (PubMed:20851901). Ethanolamine-binding by the small channels has been hypothesized to stabilize the EutL central pore in a closed (non-transporting) state. An open pore is thought to be large enough to transport ATP and/or cobalamin (By similarity). Amine and polyamine degradation; ethanolamine degradation. Homotrimerizes to form a pseudohexamer (PubMed:19194002, PubMed:19451619, PubMed:20851901, PubMed:20044574). The trimers form a two-dimensional array about 37 Angstroms thick (PubMed:19451619, PubMed:20044574). Has 2 BMC domains which can evolve independently of each other. Belongs to the EutL/PduB family. In strain MG1655 the eut operon is interrupted by the CPZ-55 prophage, encoding 9 genes situated between eutA and eutB, which are translated in the other direction. CPZ-55 may prevent expression of the eut operon in strain MG1655. Strain W3110 does not have this prophage element and should be able to express the operon.