ISG15-like
Description
ISG15-like (Interferon-stimulated gene 15 - like) systems (also known as Bil systems for Bacterial ISG15-like systems) are a 4-gene defense system comprising a homolog of ubiquitin-like ISG15 (BilA), ubiquitin-conjugating enzymes E1 (BilD) and E2 (BilB), and a deubiquitinase (BilC) (N/A, N/A) . It has been shown to defend against multiple coliphages (N/A) . The Bil system is analogous to the ISG15 system in humans, which protects against viruses.
Molecular mechanism
Hör et al., have shown that the ISG15-like system defends bacteria against phages by impairing the infectivity of newly synthesized phages. It does so by preventing tail assembly that leads to non-infective tailless phages or by producing modified tails with an obstructed tail tip that are not capable of infecting. More specifically, BilA is conjugated to the central tail fiber (CTF) protein of the phage (N/A) .
Example of genomic structure
The ISG15-like is composed of 4 proteins: BilA, BilB, BilC and BilD.
Here is an example found in the RefSeq database:
The ISG15-like system in Caulobacter segnis (GCF_023935105.1, NZ_CP096040) is composed of 4 proteins BilA (WP_252632187.1) BilB (WP_252632188.1) BilC (WP_252632189.1) BilD (WP_252632190.1)