1. Isolation of crustacean erythrophore concentrating hormone from nerve tissue of Homarus americanus
H Jaffe, M Loeb, D K Hayes, N Talbot, S Garvick Comp Biochem Physiol C Comp Pharmacol Toxicol. 1984;78(2):397-401. doi: 10.1016/0742-8413(84)90105-1.
Crustacean erythrophore concentrating hormone (CECH) was isolated from lobster (Homarus americanus) eyestalks by reverse phase high-performance liquid chromatography (rp-hplc). Putative lobster CECH fractions co-chromatographed with commercially available pure CECH on two independent rp-hplc systems, and were positive for activity by bioassay. CECH was detected in eyestalk, but not brain homogenates.
2. Peptides of the adipokinetic hormone/red pigment-concentrating hormone family: a new take on biodiversity
Gerd Gäde Ann N Y Acad Sci. 2009 Apr;1163:125-36. doi: 10.1111/j.1749-6632.2008.03625.x.
Peptides of the adipokinetic hormone (AKH)/red pigment-concentrating hormone (RPCH) family in insects are involved in the mobilization of stored macromolecules in the fat body by activating glycogen phosphorylase or triacylglycerol lipase to increase the levels of circulating metabolites (trehalose, diacylglycerols, and also proline) during periods of intense muscular activity. Here I review the biodiversity of these peptides and outline how the 47 known bioanalogues are distributed between the different insect orders and in which species they occur.
3. Insights into the Activation of a Crustacean G Protein-Coupled Receptor: Evaluation of the Red Pigment-Concentrating Hormone Receptor of the Water Flea Daphnia pulex (Dappu-RPCH R)
Graham E Jackson, Gerd Gäde Biomolecules. 2021 May 10;11(5):710. doi: 10.3390/biom11050710.
The validation of a previously developed model of the interaction between the red pigment-concentrating hormone of Daphnia pulex and its cognate receptor (Jackson et al., IJBM 106, 969-978, 2018) was undertaken. Single amino acid replacements, noticeably an Ala scan, of the ligand, Dappu-RPCH, were docked to the receptor, and the binding energies calculated and compared to the one with Dappu-RPCH. As a second step, the same molecules were docked using molecular dynamics (MD) in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane. Changes in binding energy were compared to previous results on in vitro receptor activation (Marco et al., Sci. Rep. 7, 6851, 2017). Residue scanning and MD simulations both gave comparable results for binding energy. For most mutants, there was a good inverse correlation between in vitro activity and binding. There were, however, exceptions; for example: [Ala4]Dappu-RPCH bound as tightly as the cognate ligand but had little activity. This seeming discrepancy was explained when the MD data were analyzed in detail, showing that, although [Ala4]Dappu-RPCH had multiple interactions with the receptor accounting for the high binding energy, the interacting residues of the receptor were quite different to those of Dappu-RPCH. The MD calculations show clearly that the strong binding affinity of the ligand to the receptor is not sufficient for activation. Interaction of the binding of the ligand to two residues of the receptor, Ser 155 and Gln 237, is also essential. A comparison of our computational results with the experimental results of Marco et al. and comparison with the extensive data on GnRH supports the validity of our Dappu-RPCH R model.
