Cytoplasmic inclusion of TAR DNA-binding protein 43 (TDP-43) is a hallmark of most ALS (amyotrophic lateral sclerosis) and FTLD (Frontotemporal dementia), yet the aggregation of TDP-43 remains unclear. In this study, we proved the existence of amyloid-like structures of C-terminal domain of TDP-43 (TDP-C) in bacterial inclusion bodies (lBs), and obtained a homogenous fibril sample by seeding from the components of aggregated TDP-C in Escherichia coli IBs. The results from solid-state NMR spectroscopy suggest that the homogenous fibrils were seeded from a tiny amount of aggregated TDP-C compositions in [Bs; the structure characteristics of the rigid fibril core are identified of beta-rich structures, and show subtle relativity with the hydrophobicity of residues. Our study here provides a further understanding of TDP-43 protein aggregation and fibrillation. (C) 2020 Elsevier Inc. All rights reserved.