PDBsum entry 2yyf

Toxin

PDB id: 2yyf

Contents

Protein chain

15 a.a.

PDB id:

2yyf

Name:

Toxin

Title:

Purification and structural characterization of a d-amino acid containing conopeptide, marmophine, from conus marmoreus

Structure:

M-conotoxin mr12. Chain: a. Synonym: mr1931. Engineered: yes

Source:

Synthetic: yes. Other_details: this sequence occurs naturally in conus marmoreus

NMR struc:

20 models

Authors:

F.Huang,W.Du,Y.Han,C.Wang

Key ref:

Y.Han et al. (2008). Purification and structural characterization of a D-amino acid-containing conopeptide, conomarphin, from Conus marmoreus. Febs J, 275, 1976-1987. PubMed id: 18355315

Date:

29-Apr-07 Release date: 08-Apr-08

Protein chain

B2KPN7  (COMA_CONMR) -  Conomarphin from Conus marmoreus

Seq: 71 a.a.

Struc: 15 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Febs J 275:1976-1987 (2008)

PubMed id: 18355315

Purification and structural characterization of a D-amino acid-containing conopeptide, conomarphin, from Conus marmoreus.

Y.Han, F.Huang, H.Jiang, L.Liu, Q.Wang, Y.Wang, X.Shao, C.Chi, W.Du, C.Wang.

ABSTRACT

Cone snails, a group of gastropod animals that inhabit tropical seas, are capable of producing a mixture of peptide neurotoxins, namely conotoxins, for defense and predation. Conotoxins are mainly disulfide-rich short peptides that act on different ion channels, neurotransmitter receptors, or transporters in the nervous system. They exhibit highly diverse compositions, structures, and biological functions. In this work, a novel Cys-free 15-residue conopeptide from Conus marmoreus was purified and designated as conomarphin. Conomarphin is unique because of its D-configuration Phe at the third residue from the C-terminus, which was identified using HPLC by comparing native conomarphin fragments and the corresponding synthetic peptides cleaved by different proteases. Surprisingly, the cDNA-encoded precursor of conomarphin was found to share the conserved signal peptide with other M-superfamily conotoxins, clearly indicating that conomarphin should belong to the M-superfamily, although conomarphin shares no homology with other six-Cys-containing M-superfamily conotoxins. Furthermore, NMR spectroscopy experiments established that conomarphin adopts a well-defined structure in solution, with a tight loop in the middle of the peptide and a short 3(10)-helix at the C-terminus. By contrast, no loop in L-Phe13-conomarphin was found, which suggests that D-Phe13 is essential for the structure of conomarphin. In conclusion, conomarphin may represent a new conotoxin family, whose biological activity remains to be identified.