The Glycoprotein NOWA and Minicollagens Are Part of a Disulfidelinked Polymer That Forms the Cnidarian Nematocyst Wall*
- Suat Özbek‡§,
- Elena Pokidysheva‡,
- Martine Schwager‡,
- Therese Schulthess‡,
- Naushaba Tariq‡,
- Dirk Barth¶,
- Alexander G. Milbradt¶,
- Luis Moroder¶,
- Jürgen Engel‡ and
- Thomas W. Holstein∥
- ‡Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland, the ¶Max-Planck-Institute for Biochemistry, D-82152 Martinsried, Germany, and the ∥Institute of Zoology, Technical University of Darmstadt, Schnittpahnstrasse 10, D-64287 Darmstadt, Germany
- ↵§ To whom correspondence should be addressed. Tel.: 41612672204; Fax: 41612672189; E-mail: Suat.Oezbek{at}unibas.ch.
Abstract
The nematocyst is a unique extrusive organelle involved in the defense and capture of prey in cnidarians. Minicollagens and the glycoprotein NOWA are major components of the nematocyst capsule wall, which resists osmotic pressure of 15 MPa. Here we present the recombinant expression of NOWA, which spontaneously assembles to globular macromolecular particles that are sensitive to reduction as the native wall structure. Ultra-structural analysis showed that the Hydra nematocyst wall is composed of several layers of globular particles, which are interconnected via radiating rodlike protrusions. Evidence is presented that native wall particles contain NOWA and minicollagen, supposed to be linked via disulfide bonds between their homologous cysteine-rich domains. Our data suggest a continuous suprastructure of the nematocyst wall, assembled from wall proteins that share a common oligomerization motif.
- Received July 7, 2004.
- Revision received September 29, 2004.
- The American Society for Biochemistry and Molecular Biology, Inc.
