Hami in Archaebacteria: Structure and Function

Definition: Hamus (Singular) is an archaeal cell surface appendage; a long helical tube with three nano hooks or tripartite hooks at the far end.

• Hamus in Latin means "hook" or "fishing rod"
• Each archaeal cell is surrounded by a halo of about 100 hami (Plural)
• The hami are mainly composed of 120 kDa subunits protein
• Hami is stable in a broad temperature and pH range (0-70 degrees C; 0.5-11.5 pH range). 
• It is a unique hook like structure in archaea discovered by Moissi et al in 2005

Function:

• Cell to Cell attachment. End hooks of hami helps in firm attachment forming an organized community or biofilms.
• Cell to Surface attachment: Helps in attaching to other surfaces or other microbes.

Watch our 2 minute video for better understanding

Reference:

Perras, A. K., Wanner, G., Klingl, A., Mora, M., Auerbach, A. K., Heinz, V., & Moissl-Eichinger, C. (2014). Grappling archaea: ultrastructural analyses of an uncultivated, cold-loving archaeon, and its biofilm. Frontiers in microbiology, 5, 397.

Moissi C, Rachel R, Briegel A, Engelhardt H, Huber R. The unique structure of archaeal 'hami', highly complex cell appendages with nano-grappling hooks. Mol Microbiol. 2005 Apr;56(2):361-70.