Bacterial inclusion bodies contain amyloid-like structure.
Protein aggregation is a process in which identical proteins self-associate into imperfectly ordered macroscopic entities. Such aggregates are generally classified as amorphous, lacking any long-range order, or highly ordered fibrils. Protein fibrils can be composed of native globular molecules, such as the hemoglobin molecules in sickle-cell fibrils, or can be reorganized beta-sheet-rich aggregates, termed amyloid-like fibrils. Amyloid fibrils are associated with several pathological conditions in humans, including Alzheimer disease and diabetes type II. We studied the structure of bacterial inclusion bodies, which have been believed to belong to the amorphous class of aggregates. We demonstrate that all three in vivo-derived inclusion bodies studied are amyloid-like and comprised of amino-acid sequence-specific cross-beta structure. These findings suggest that inclusion bodies are structured, that amyloid formation is an omnipresent process both in eukaryotes and prokaryotes, and that amino acid sequences evolve to avoid the amyloid conformation.
Wang
Lei
L
Structural Biology Laboratory, The Salk Institute, La Jolla, California, United States of America.
Maji
Samir K
SK
Sawaya
Michael R
MR
Eisenberg
David
D
Riek
Roland
R
D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism*; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein / Q000235:genetics; D063308:Myelin-Oligodendrocyte Glycoprotein; D017433:Protein Structure, Secondary; D051381:Rats; D016212:Transforming Growth Factor beta / Q000235:genetics
D000682:Amyloid; D000942:Antigens, Bacterial; C525718:BMP2 protein, human; D001426:Bacterial Proteins; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; C571326:MOG protein, human; C571328:Mog protein, rat; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein; D063308:Myelin-Oligodendrocyte Glycoprotein; D016212:Transforming Growth Factor beta