Activity of the Mitogenic Pasteurella multocida Toxin Requires an Essential C-Terminal Residue
AUTOR(ES)
Ward, Philip N.
FONTE
American Society for Microbiology
RESUMO
Pasteurella multocida toxin (PMT) is a potent mitogen that also affects bone resorption. PMT acts intracellularly and is therefore postulated to have several domains involved in different aspects of its function. The toxin contains eight cysteine residues. Mutants with individual substitutions for each of these residues were constructed, and the effects of these on the biological activity of the toxin were determined by cultured-cell assays. Only the most C-terminal of the eight cysteines (C1165) was essential for full activity, although mutation of the cysteine residue at position 1159 caused a slight but reproducible loss of potency. In animal challenge experiments, mutant toxin (C1165S) was not toxic to piglets, even at doses exceeding a lethal dose of active PMT 1,000-fold. The mutant and wild-type toxins displayed identical purification characteristics, similar susceptibility to proteolytic digestion, and circular dichroism profiles, which indicated that no gross structural changes had taken place. The function of the essential C1165 residue is not yet known, although its most likely role is an enzymatic one at or near the catalytic center of the toxin.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=108712Documentos Relacionados
- Biological Activity of a C-Terminal Fragment of Pasteurella multocida Toxin
- The Kex2p Proregion Is Essential for the Biosynthesis of an Active Enzyme and Requires a C-terminal Basic Residue for Its Function
- Localization of Functional Domains of the Mitogenic Toxin of Pasteurella multocida
- Arabidopsis C-terminal domain phosphatase-like 1 and 2 are essential Ser-5-specific C-terminal domain phosphatases
- C-Terminal Regions of the Human Telomerase Catalytic Subunit Essential for In Vivo Enzyme Activity