The glycoprotein NOWA and minicollagens are part of a disulfide-linked polymer that forms the cnidarian nematocyst wall.
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.
Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. Suat.Oezbek@unibas.ch
Suat
S
Ozbek
Elena
E
Pokidysheva
Martine
M
Schwager
Therese
T
Schulthess
Naushaba
N
Tariq
Dirk
D
Barth
Alexander G
AG
Milbradt
Luis
L
Moroder
Jürgen
J
Engel
Thomas W
TW
Holstein
D000818:Animals; D001483:Base Sequence; D001704:Biopolymers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003094:Collagen / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004220:Disulfides / Q000737:chemistry; D006829:Hydra / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D001704:Biopolymers; D004220:Disulfides; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D003094:Collagen; D004247:DNA