Cloning and characterization of neuraminidase from Salmonella typhimurium LT-2 and its relationship to neuraminidase from other bacteria

Bacterial neuraminidases (NANases) have been proposed to be bacterial virulence factors because of their ability to cleave sialic acid residues from host glycoconjugates. The gene encoding NANase (nanH) from Salmonella typhimurium has been cloned and its protein product purified. The purified NANase is 41.3 kD with an isoelectric point of approximately 9.0. The enzyme does not require Ca$\sp{++}$ for maximal activity and is not affected by EDTA or EGTA. S. typhimurium NANase is insensitive to N-acetylneuraminic acid (NeuNAc) and dithiothreitol. Compared to many previously studied NANases, the S. typhimurium NANase is relatively unaffected by the competitive inhibitor, 2-deoxy-2, 3-dehydro-NeuNAc. NANase activity is maximal at a sodium chloride concentration of approximately 100 mM and is not altered in the presence of increasing ionic strength. K$\sb{\rm m}$ and V$\sb{\rm max}$ values for the synthetic substrate 4-methylumbelliferyl-NeuNAc are 0.24 mM and 5200 nmol/min, respectively. In general, α-(2-3)-linked sialic acid glycosides are preferentially cleaved by the S. typhimurium NANase. The enzyme hydrolyzes ganglioside substrates more rapidly than the glycoprotein or polysaccharide substrates assayed.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Veterinary Biosciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Hoyer, Lois Lawrisuk

Contributors dc:contributor

• Vimr, Eric R.

• Biology, Molecular
• Biology, Genetics
• Biology, Microbiology

Statement dc:rights

• Copyright 1989 Hoyer, Lois Lawrisuk

Language dc:language

eng

Identifier

AAI9010895
(UMI)AAI9010895

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/21308