4TR5: C3larvin Toxin, An Adp-ribosyltransferase From Paenibacillus Larvae

C3larvin toxin was identified by a bioinformatic strategy as a putative mono-ADP-ribosyltransferase and a possible virulence factor from Paenibacillus larvae, which is the causative agent of American Foulbrood in honey bees. C3larvin targets RhoA as a substrate for its transferase reaction, and kinetics for both the NAD(+) (Km = 34 +/- 12 mum) and RhoA (Km = 17 +/- 3 mum) substrates were characterized for this enzyme from the mono-ADP-ribosyltransferase C3 toxin subgroup. C3larvin is toxic to yeast when expressed in the cytoplasm, and catalytic variants of the enzyme lost the ability to kill the yeast host, indicating that the toxin exerts its lethality through its enzyme activity. A small molecule inhibitor of C3larvin enzymatic activity was discovered called M3 (Ki = 11 +/- 2 mum), and to our knowledge, is the first inhibitor of transferase activity of the C3 toxin family. C3larvin was crystallized, and its crystal structure (apoenzyme) was solved to 2.3 A resolution. C3larvin was also shown to have a different mechanism of cell entry from other C3 toxins.
PDB ID: 4TR5Download
MMDB ID: 125671
PDB Deposition Date: 2014/6/14
Updated in MMDB: 2014/12
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 4TR5: monomeric; determined by author and by software (PISA)
Molecular Components in 4TR5
Label Count Molecule
Protein (1 molecule)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB