A self-assembled nanocompartment in anammox bacteria for resisting intracelluar hydroxylamine stress.

Anammox bacteria play an important role in the global nitrogen cycle, but research on anammoxosome structure is still in its initial stages. In particular, the anammox bacteria genome contains nanocompartments gene loci. However, the function and structure of the nanocompartments in anammox bacteria is poorly understood. We apply genetic engineering to demonstrate the self-assembled nanocompartments of anammox bacteria. The encapsulin shell protein (cEnc) and cargo protein hydroxylamine oxidoreductase (HAO) can self-assemble to form regular nanocompartments (about 128 nm in diameter) in vitro. Cell growth curve tests show that nanocompartments help model bacteria resist hydroxylamine (NHOH) stress. Batch test results and transcriptional data show that cEnc and HAO are highly expressed in response to the negative effects of NHOH on anammox efficiency, predicting a potential role of nanocompartments in helping anammox bacteria resist NHOH stress. These findings improve our understanding of the mechanisms by which anammox bacteria respond to harmful environmental metabolites.