Protein Domain : NAD--protein ADP-ribosyltransferase Alt-like IPR016225

Type	Family
Description	This entry represents a family of NAD-protein ADP-ribosyltransferases found in Myoviridae (phages with contractile tails). It includes the ALT protein from the bacteriophage T4Protein ADP-ribosylation is an important posttranslational modification catalyzed by a group of enzymes known as ADP-ribosyltransferases (ADP-RTs) [ ]. ADP-RTs transfer single or multiple ADP-ribose moieties from NAD to a specific amino acid residue within a target protein, forming mono ADP-ribosylation or poly ADP-ribosylation (PARylation) []. ADP-ribosylation changes the electrostatic potential of a target protein by introducing two phosphate groups and may affect protein-DNA as well as protein-protein interactions []. Protein ADP-ribosylation plays versatile roles in multiple biological processes.Bacteriophage T4 codes for three ADP-ribosyltransferases: Alt, ModA, and ModB. The ADP-ribosylating activity of each is directed to a specific set of host proteins. Among the three phage-encoded T4 mono-ADP-RTs, the Alt protein has the broadest range of target proteins, which include one of the two alpha subunits of host RNA polymerase [ ].The T4 Alt protein initially acts as a structural component of the phage head. At the time of infection, it enters the host cell with phage DNA and immediately displays enzymatic activity [].
Short Name	Phage_T4_Alt-like