Abstract

Ignicoccus hospitalis forms many cell surface appendages, the Iho670 fibers (width, 14 nm; length, up to 20 mu m), which constitute up to 5% of cellular protein. They are composed mainly of protein Iho670, possessing no homology to archaeal flagellins or fimbrins. Their existence as structures different from archaeal flagella or fimbriae have gone unnoticed up to now because they are very brittle.