RNase D is one of the seven exoribonucleases identified in E. coli. It is an 3'-5' exoribonuclease

Exoribonuclease

An exoribonuclease is an exonuclease ribonuclease, which are enzymes that degrade RNA by removing terminal nucleotides from either the 5' end or the 3' end of the RNA molecule...

 and which has been shown to be involved in the 3' processing of various stable RNA molecules ; It is known to add the 3' CCA sequence to tRNA in prokaryotic tRNA processing. RNase D has homologues

Homology (biology)

Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 in many other organisms. When a part of another larger protein has a domain

Protein domain

A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...

that is very similar to RNase D, this is called an RNase D domain.

External links

• Crystal structure of E. coli RNase D at the RCSB Protein Data Bank