Identification and characterization of P. fucata and C. gigas ELH-like peptides. (A) Amino acid sequences of P. fucata and C.gigas ELH precursors. (B) Schematics showing ELH precursors identified in molluscs. (C) Comparative sequence alignment and (D) Phylogenetic analysis of bioactive ELH/DH44/CRH region between species. Sequence logo is shown above alignments. (E) Protein models of oyster ELH1 and ELH2 assembled from molecular dynamics simulation. Secondary structures: blue, helix; purple, alpha-helix; cyan, turn; white, random coil; dark yellow, isolated beta bridge. (F) Off-line nLC-MALDI tandem MS analysis of Crassotrea gigas cerebral ganglia. MS/MS spectrum of the egg-laying hormone Cg-ELH2 m/z 3939. Immonium, a-, b- and y-ions detected are marked.