Protein Family Models

Contact-dependent growth inhibition (CDI) systems encode polymorphic toxin/immunity proteins that mediate competition between neighboring bacterial cells. CDI is mediated by the CdiB/CdiA family of two-partner secretion proteins. This domain represents the C-terminal of CdiA proteins (CdiA-CT), which contains the CDI toxin activity. The C-terminal nuclease domain forms a stable complex with its cognate immunity protein. It is also sufficient to inhibit growth when expressed in E. coli cells, consolidating the idea that they constitute the functional CDI toxin. The CdiA-CT C-terminal domains are structurally similar to type IIS restriction endonucleases suggesting that the toxins have metal-dependent DNase activity [1]. [1]. 23236156. Structural basis of toxicity and immunity in contact-dependent. growth inhibition (CDI) systems.. Morse RP, Nikolakakis KC, Willett JL, Gerrick E, Low DA, Hayes. CS, Goulding CW;. Proc Natl Acad Sci U S A. 2012;109:21480-21485. (from Pfam)

Date:

2024-04-03

Sequences in this family appear primarily as domain within minor head proteins of double-stranded DNA phage that are described as morphogenesis proteins, but occur also as a domain N-terminal to the NAD+--arginine ADP-ribosyltransferase domain of toxin EFV of Enterococcus faecalis. Phage minor head protein examples include Gp7 of SPP1 and protein F (Gp30) of phage Mu.

Date:

2023-12-12

This HMM describes a region of about 110 amino acids found exclusively in phage-related proteins, internally or toward the C-terminus. One member, gp7 of phage SPP1, appears involved in head morphogenesis.

Date:

2021-05-12