PDBsum entry 2nx7

Structural protein

PDB id: 2nx7

Contents

Protein chain

28 a.a.

PDB id:

2nx7

Name:

Structural protein

Title:

Structure of nowa cysteine rich domain 8

Structure:

Nematocyst outer wall antigen. Chain: a. Fragment: domain 8. Engineered: yes

Source:

Hydra vulgaris. Organism_taxid: 6087. Gene: nowa. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

10 models

Authors:

S.Meier,P.R.Jensen,P.Adamczyk,H.P.Bachinger,T.W.Holstein,J.Engel, S.Ozbek,S.Grzesiek

Key ref:

S.Meier et al. (2007). Sequence-Structure and Structure-Function Analysis in Cysteine-rich Domains Forming the Ultrastable Nematocyst Wall. J Mol Biol, 368, 718-728. PubMed id: 17362991 DOI: 10.1016/j.jmb.2007.02.026

Date:

17-Nov-06 Release date: 02-Oct-07

Protein chain

Q8IT70  (Q8IT70_HYDVU) -  Nematocyst outer wall antigen from Hydra vulgaris

Seq: 774 a.a.

Struc: 28 a.a.

DOI no: 10.1016/j.jmb.2007.02.026

J Mol Biol 368:718-728 (2007)

PubMed id: 17362991

Sequence-Structure and Structure-Function Analysis in Cysteine-rich Domains Forming the Ultrastable Nematocyst Wall.

S.Meier, P.R.Jensen, P.Adamczyk, H.P.Bächinger, T.W.Holstein, J.Engel, S.Ozbek, S.Grzesiek.

ABSTRACT

The nematocyst wall of cnidarians is a unique biomaterial that withstands extreme osmotic pressures, allowing an ultrafast discharge of the nematocyst capsules. Assembly of the highly robust nematocyst wall is achieved by covalent linkage of cysteine-rich domains (CRDs) from two main protein components, minicollagens and nematocyst outer wall antigen (NOWA). The bipolar minicollagens have different disulfide patterns and topologies in their N and C-terminal CRDs. The functional significance of this polarity has been elusive. Here, we show by NMR structural analysis that all representative cysteine-rich domains of NOWA are structurally related to N-terminal minicollagen domains. Natural sequence insertions in NOWA CRDs have very little effect on the tightly knit domain structures, nor do they preclude the efficient folding to a single native conformation. The different folds in NOWA CRDs and the atypical C-terminal minicollagen domain on the other hand can be directly related to different conformational preferences in the reduced states. Ultrastructural analysis in conjunction with aggregation studies argues for an association between the similar NOWA and N-terminal minicollagen domains in early stages of the nematocyst wall assembly, which is followed by the controlled association between the unusual structures of C-terminal minicollagen domains.

Selected figure(s)

Figure 1.
Figure 1. Domain organization of NOWA and minicollagen 1. (a) Schematic modular arrangement of signal peptide (SP), sperm-coating protein (SCP) domain, C-type lectin domain (CTLD) and cysteine-rich octarepeat domain (CROD) in NOWA; CRDs are indicated as circles and coloured according to sequence similarity; CRDs in minicollagen1 are known to form different structures. (b) Sequence alignment of the eight CRDs in the NOWA octarepeat domain and comparison to N and C-terminal CRDs of Hydra minicollagen 1 (Mcol1hN and Mcol1hC).^10

Figure 4.
Figure 4. A stereo representation of the NOWA CRD domain structures.^12 The structure, disulfide pattern and turn topology is conserved in the NOWA fold upon natural insertions into the structure at the indicated location.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 368, 718-728) copyright 2007.

Figures were selected by the author.