Shell component of a type 1 encapsulin nanocompartment in situ; its cargo protects against oxidative stress at low pH. In situ and in E.coli assembles into proteinaceous shells about 22 nm in diameter with 2.5 nm thick walls (PubMed:34751132, PubMed:24855650). Cargo proteins are targeted to the interior via their C-terminal extensions; empty intact shells can be isolated in E.coli in the absence of cargo protein. There are at least 4 possible cargo proteins, DyP (encoded in the same locus), FolB, BfrB and Rv1762c; DyP and Rv1762c have been identified in vivo (PubMed:24855650). Probably involved in protection against oxidative damage from the host immune response (Probable) (PubMed:34751132). A T-cell antigen found in bacterial culture cell filtrates, stimulates mouse immune response. Does not have detectable bacteriocin activity (PubMed:9596740). Multimeric (PubMed:9596740). The encapsulin nanocompartment is formed by 60 subunits (Probable). Monomers form pentamers which assemble to form shells. There are 12 pores where the pentamers meet as well as 3-fold axis channels and dimer channels; none are larger than 3-4 Angstroms in diameter. The N-terminus of the protein is inside the shell, the C-terminus is outside (Probable). Encapsulin microcompartments of this protein encapsulating DyP are found in situ (PubMed:34751132). Detected at low levels in short-term culture filtrate, the nanocompartment is very stable and may survive cell lysis, explaining its apparent secretion (PubMed:9596740) (Probable). Detected in infected host (mouse J774 cell line) exosomes (PubMed:20662102). The initiator methionine is partially removed. When isolated from culture filtrate isoelectric focusing gives 3 bands, none of which are glycosylated. A single enc deletion survives less well after 3 days in 2.5 mM H2O2, pH 4.5 (mimics growth in the phagolysosome). A double dyp-enc deletion mutant cannot produce encapsulin nanocompartments, cells are highly sensitive to H2O2 at pH 4.5, mutants exhibit significant dysregulation of redox homeostasis, survive less well in C57BL/6 mouse-derived bone marrow cells and are more sensitive to pyrazinamide treatment in infected BALB/C mice. Stimulates a strong IFN-gamma response in memory immune C57BL/6J mouse spleen T cells, recognized by monoclonal antibody HYB 71-2. Belongs to the encapsulin family. Family 1 subfamily.