کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2030513 | 1071212 | 2011 | 11 صفحه PDF | دانلود رایگان |
SummaryThe virulence of Gram-positive bacteria is enhanced by toxins like the Streptococcus pyogenes β-NAD+ glycohydrolase known as SPN. SPN-producing strains of S. pyogenes additionally express the protein immunity factor for SPN (IFS), which forms an inhibitory complex with SPN. We have determined crystal structures of the SPN-IFS complex and IFS alone, revealing that SPN is structurally related to ADP-ribosyl transferases but lacks the canonical binding site for protein substrates. SPN is instead a highly efficient glycohydrolase with the potential to deplete cellular levels of β-NAD+. The protective effect of IFS involves an extensive interaction with the SPN active site that blocks access to β-NAD+. The conformation of IFS changes upon binding to SPN, with repacking of an extended C-terminal α helix into a compact shape. IFS is an attractive target for the development of novel bacteriocidal compounds functioning by blocking the bacterium's self-immunity to the SPN toxin.
► SPN is structurally homolgous to ADP-ribosyl transferase
► IFS interacts extensively with SPN, blocking access to the SPN active site
► IFS adopts different conformations in solution and when bound to SPN
Journal: - Volume 19, Issue 2, 9 February 2011, Pages 192–202