A nonspecific, single-stranded nuclease activity with characteristics of atopoisomerase found in a major grass pollen allergen: Possible biological significance

Citation
A. Bufe et al., A nonspecific, single-stranded nuclease activity with characteristics of atopoisomerase found in a major grass pollen allergen: Possible biological significance, BIOL CHEM, 380(7-8), 1999, pp. 1009-1016
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOLOGICAL CHEMISTRY
ISSN journal
1431-6730 → ACNP
Volume
380
Issue
7-8
Year of publication
1999
Pages
1009 - 1016
Database
ISI
SICI code
1431-6730(199907/08)380:7-8<1009:ANSNAW>2.0.ZU;2-R
Abstract
The major allergen from timothy grass pollen, Phlp5b (Phleum pratense), was shown to exhibit ribonuclease activity. It turned out that the C-terminal portion of this molecule was the biologically active domain. Here evidence is presented that the allergen is a single-stranded, sugar-nonspecific nucl ease with topoisomerase activity. An isomerase-specific active site was ide ntified, and a non-active mutant was constructed by site directed mutagenes is, and showed no nucleolytic activity. In contrast to the wild type (WT), the mutant did not dimerize. Although the binding capacity of IgE antibodie s toward the mutant was reduced as compared to the WT, the allergenic activ ity was retained. We conclude that the allergen Phlp5b is a single-stranded nuclease with an unusual topoisomerase-like activity. This biological acti vity is not by itself connected to the allergenicity of the molecule. Wheth er the enzymatic activity is responsible for the induction of the allergic sensitization and inflammation remains an open question.