title: Structure, Function and Evolution of Clostridium botulinum C2 and C3 Toxins: Insight to Poultry and Veterinary Vaccines.
abstract: Clostridium botulinum group III strains are able to produce cytotoxins, C2 toxin and C3 exotoxin, along with botulinum neurotoxin types C and D. C2 toxin and C3 exotoxin produced by this organism are the most important members of bacterial ADP-ribosyltransferase superfamily. Both toxins have distinct pathophysiological functions in the avian and mammalian hosts. The members of this superfamily transfer an ADP-ribose moiety of NAD+ to specific eukaryotic target proteins. The present review describes the structure, function and evolution aspects of these toxins with a special emphasis to the development of veterinary vaccines. C2 toxin is a binary toxin that consists of a catalytic subunit (C2I) and a translocation subunit (C2II). C2I component is structurally and functionally similar to the VIP2 and iota A toxin whereas C2II component shows a significant homology with the protective antigen from anthrax toxin and iota B. Unlike C2 toxin, C3 toxin is devoid of translocation/binding subunit. Extensive studies on their sequence-structure-function link spawn additional efforts to understand the catalytic mechanisms and target recognition. Structural and functional relationships with them are often determined by using evolutionary constraints as valuable biological measures. Enzyme-deficient mutants derived from these toxins have been used as drug/protein delivery systems in eukaryotic cells. Thus, current knowledge on their molecular diversity is a well-known perspective to design immunotoxin or subunit vaccine for C. botulinum infection.
authors.affiliation: Molecular Systems Engineering Lab, Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu. India.
authors.forename: Paulchamy
authors.initials: P
authors.lastname: Chellapandi
authors.forename: Arokiyasamy
authors.initials: A
authors.lastname: Prisilla
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001428:Bacterial Vaccines / Q000096:biosynthesis / Q000276:immunology; D001905:Botulinum Toxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001906:Botulism / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D020134:Catalytic Domain; D003014:Clostridium botulinum / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity*; D019143:Evolution, Molecular; D015870:Gene Expression; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010802:Phylogeny; D011200:Poultry / Q000382:microbiology*; D011201:Poultry Diseases / Q000276:immunology / Q000382:microbiology* / Q000473:pathology / Q000517:prevention & control; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D007527:Isoenzymes; C030325:anthrax toxin; D001905:Botulinum Toxins; C096324:botulinum toxin type C
keywords: Veterinary vaccines; immunotoxin; molecular evolution; molecular pathogenesis.; subunit vaccine clostridium botulinum