TET peptidases: A family of tetrahedral complexes conserved in prokaryotes

Biochimie. 2016 Mar;122:188-96. doi: 10.1016/j.biochi.2015.11.001. Epub 2015 Nov 4.


The TET peptidases are large polypeptide destruction machines present among prokaryotes. They form 12-subunits hollow tetrahedral particles, and belong to the family of M42 metallo-peptidases. Structural characterization of various archaeal and bacterial complexes has revealed a unique mechanism of internal compartmentalization and peptide trafficking that distinguishes them from the other oligomeric peptidases. Different versions of the TET complex often co-exist in the cytosol of microorganisms. In depth enzymatic studies have revealed that they are non-processive cobalt-activated aminopeptidases and display contrasting substrate specificities based on the properties of the catalytic chambers. Recent studies have shed light on the assembly mechanism of homo and hetero-dodecameric TET complexes and shown that the activity of TET aminopeptidase towards polypeptides is coupled with its assembly process. These findings suggested a functional regulation based on oligomerization control in vivo. This review describes a current knowledge on M42 TET peptidases biochemistry and discuss their possible physiological roles. This article is a part of the Special Issue entitled: «A potpourri of proteases and inhibitors: from molecular toolboxes to signalling scissors».

Keywords: Aminopeptidase; Intracellular proteolysis; Large molecular assemblies; M42; TET.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Aminopeptidases / chemistry*
  • Aminopeptidases / genetics
  • Aminopeptidases / metabolism
  • Metals / chemistry
  • Metals / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Prokaryotic Cells / enzymology*
  • Protein Multimerization*
  • Protein Structure, Quaternary*
  • Sequence Homology, Amino Acid
  • Substrate Specificity


  • Metals
  • Aminopeptidases