C3larvin toxin, an ADP-ribosyltransferase from Paenibacillus larvae Journal Article
| Authors: | Krska, D.; Ravulapalli, R.; Fieldhouse, R. J.; Lugo, M. R.; Merrill, A. R. |
| Article Title: | C3larvin toxin, an ADP-ribosyltransferase from Paenibacillus larvae |
| Abstract: | 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 μM) and RhoA (Km = 17 ± 3 μM) 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 μM), 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. |
| Keywords: | controlled study; protein expression; unclassified drug; nonhuman; animal cell; mouse; cytology; enzyme inhibitor; enzyme activity; enzyme analysis; sequence alignment; cytoplasm; rhoa guanine nucleotide binding protein; crystal structure; conformational transition; yeast; catalysis; crystallization; molecular docking; bioinformatics; enzyme substrate complex; nicotinamide adenine dinucleotide adenosine diphosphate ribosyltransferase; enzymes; substrates; enzyme mechanism; crystallography; different mechanisms; toxic materials; virulence factors; virulence factor; reaction kinetics; enzyme variant; article; toxin analysis; enzymatic activities; small molecule inhibitor; paenibacillus; ic50; adp-ribosyltransferase; american foulbrood; paenibacillus larvae; transferase reactions; c3 larvin toxin; compound m3; toxicokinetics; apis mellifera |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 290 |
| Issue: | 3 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 2015-01-16 |
| Start Page: | 1639 |
| End Page: | 1653 |
| Language: | English |
| DOI: | 10.1074/jbc.M114.589846 |
| PROVIDER: | scopus |
| PMCID: | PMC4340408 |
| PUBMED: | 25477523 |
| DOI/URL: | |
| Notes: | Export Date: 2 March 2015 -- Source: Scopus |
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