Submitted to: Biochemical and Biophysical Research Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2002
Publication Date: 11/9/2002
Citation: Torfs, P., Baggerman, G., Meeusen, T., Nieto, J., Nachman, R.J., Calderon, J., Deloof, A., Schoofs, L. 2002. Isolation, identification, and synthesis of a disulfated sulfakinin from the central nervous system of an arthropod the white shrimp Litopenaeus vannamei. Biochemical and Biophysical Research Communications. 299:312-320.
Interpretive Summary: Because of problems with the development of resistance to conventional pesticides, there is a critical need for new concepts and alternative approaches in controlling insect pests. The basic premise of this research is that neuropeptides (short chains of amino acids) serve as potent internal messengers in insects to regulate vital functions. New, selective control measures may be developed by designing metabolically stable mimics of these neuropeptides that actively inhibit or over-stimulate functions regulated by them, resulting in disruption of the internal environment of the insect. We report on the isolation, identification and synthesis of a member of the "sulfakinin" class of neuropeptides with a unique structure from a crustacean, the white shrimp. The structure of this shrimp neuropeptide differs from those of the same class in insects in two key structural regions. A deeper understanding of the structures of neuropeptides from insects and edible crustaceans will aid in the design of neuropeptide mimics capable of distinguishing between pests and beneficial organisms cultivated in aquaculture. The work brings us one step closer to the development of practical neuropeptide-like substances that will be effective in controlling pest insects in an environmentally friendly fashion.
Technical Abstract: Two myotropic peptides displaying tyrosyl sulfation have been isolated from an extract of central nervous systems (brain, suboesophageal ganglion, thoracic ganglia, and ventral nerve cord) of the white shrimp Litopenaeus vannemei. Both peptides were identified by mass spectrometry, and belong to the sulfakinin family of neuropeptides, which are characterized by the C-terminal hexapeptide Y(SO3H)GHMRF-NH2 preceded by two acidic amino acid residues. Pev-SK 1 (AGGSGGVGGEY(SO3H)DDY(SO3H)GH(L/I)RF-NH2) has two sulfated tyrosyl residues and a unique (L/I) M substitution in the C-terminal sequence. Pev-SK 2 (pQFDEYGHMRF-NH2) fully complies with the typical sulfakinin core sequence and is blocked by a pyroglutamyl residue. Synthetic analogs (sulfated and unsulfated) were synthesized and the tyrosyl sulfations were confirmed by myotropic activity studies and co-elution with the native fractions. Pev-SK 1 is the first disulfated neuropeptide elucidated in the phylum of the arthropoda, with the only other reported disulfated peptide, called cionin, found in a protochordate. The similarities in amino acid sequence and posttranslational modifications of the crustacean sulfakinins and protochordate cionin provide further evidence for the hypothesis stating that gastrin/CCK, cionin, and sulfakinins originate from a common ancestral gastrin/CCK-like peptide.