Proteolytic Release of the Intramolecular Chaperone Domain Confers Processivity to Endosialidase F

authored by: David Schwarzer, Katharina Stummeyer, Thomas Haselhorst, Friedrich Freiberger, Bastian Rode, Melanie Grove, Thomas Scheper, Mark Von Itzstein, Martina Mühlenhoff, Rita Gerady-Schahn
Abstract: Endosialidases (endoNs), as identified so far, are tailspike proteins of bacteriophages that specifically bind and degrade the α2,8-linked polysialic acid (polySia) capsules of their hosts. The crystal structure solved for the catalytic domain of endoN from coliphage K1F (endoNF) revealed a functional trimer. Folding of the catalytic trimer is mediated by an intramolecular C-terminal chaperone domain. Release of the chaperone from the folded protein confers kinetic stability to endoNF. In mutant c(S), the replacement of serine 911 by alanine prevents proteolysis and generates an enzyme that varies in activity from wild type. Using soluble polySia as substrate a 3-times higher activity was detected while evaluation with immobilized polySia revealed a 190-fold reduced activity. Importantly, activity of c(S) did not differ from wild type with tetrameric sialic acid, the minimal endoNF substrate. Furthermore, we show that the presence of the chaperone domain in c(S) destabilizes binding to polySia in a similar way as did selective disruption of a polySia binding site in the stalk domain. The improved catalytic efficiency toward soluble polySia observed in these mutants can be explained by higher dissociation and association probabilities, whereas inversely, an impaired processivity was found. The fact that endoNF is a processive enzyme introduces a new molecular basis to explain capsule degradation by bacteriophages, which until now has been regarded as a result of cooperative interaction of tailspike proteins. Moreover, knowing that release of the chaperone domain confers kinetic stability and processivity, conservation of the proteolytic process can be explained by its importance in phage evolution.
Organisation(s): Institute of Technical Chemistry
External Organisation(s): Hannover Medical School (MHH)
Griffith University Queensland
Type: Article
Journal: Journal of Biological Chemistry
Volume: 284
Pages: 9465-9474
No. of pages: 10
ISSN: 0021-9258
Publication date: 03.02.2009
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Biochemistry, Molecular Biology, Cell Biology
Electronic version(s): https://doi.org/10.1074/jbc.M808475200 (Access: Open)

BibTeX

@article{65276565f1da42e8b648d1de41871177,
title = "Proteolytic Release of the Intramolecular Chaperone Domain Confers Processivity to Endosialidase F",
abstract = "Endosialidases (endoNs), as identified so far, are tailspike proteins of bacteriophages that specifically bind and degrade the α2,8-linked polysialic acid (polySia) capsules of their hosts. The crystal structure solved for the catalytic domain of endoN from coliphage K1F (endoNF) revealed a functional trimer. Folding of the catalytic trimer is mediated by an intramolecular C-terminal chaperone domain. Release of the chaperone from the folded protein confers kinetic stability to endoNF. In mutant c(S), the replacement of serine 911 by alanine prevents proteolysis and generates an enzyme that varies in activity from wild type. Using soluble polySia as substrate a 3-times higher activity was detected while evaluation with immobilized polySia revealed a 190-fold reduced activity. Importantly, activity of c(S) did not differ from wild type with tetrameric sialic acid, the minimal endoNF substrate. Furthermore, we show that the presence of the chaperone domain in c(S) destabilizes binding to polySia in a similar way as did selective disruption of a polySia binding site in the stalk domain. The improved catalytic efficiency toward soluble polySia observed in these mutants can be explained by higher dissociation and association probabilities, whereas inversely, an impaired processivity was found. The fact that endoNF is a processive enzyme introduces a new molecular basis to explain capsule degradation by bacteriophages, which until now has been regarded as a result of cooperative interaction of tailspike proteins. Moreover, knowing that release of the chaperone domain confers kinetic stability and processivity, conservation of the proteolytic process can be explained by its importance in phage evolution.",
author = "David Schwarzer and Katharina Stummeyer and Thomas Haselhorst and Friedrich Freiberger and Bastian Rode and Melanie Grove and Thomas Scheper and {Von Itzstein}, Mark and Martina M{\"u}hlenhoff and Rita Gerady-Schahn",
year = "2009",
month = feb,
day = "3",
doi = "10.1074/jbc.M808475200",
language = "English",
volume = "284",
pages = "9465--9474",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "14",
}