English: A linear depiction of the alpha endorphin in the stick molecular rendering model with solvation and secondary structure such as alpha helix or beta structures.

3D structure was generated using PEP-FOLD services after no published x-ray crystallography or 2D NMR data was found to be available. Four (4) candidate structures of alpha-endorphin were formed from the original amino acid sequence, and the candidates were compared with tertiary homology to the known conformation of beta-endorphin as a peptide analog. Because all four candidates conform with the beta-endorphin structural homology test, these candidates were further distinguished by having their calculated conformational energy compared. The calculated conformational energy was generated using Avogadro 1 from the downloaded PDB files acquired from PEP-FOLD. The lowest energy candidate structure was used as the basis for the illustration.

Relevant Data in Selecting Candidate Structure (alpha-endorphin): MODEL PEP-FOLD JOB CONFORMER ENERGY (kJ/mol) -Model 06 01/26/23 23:07:48 1261.02 -Model 09A 01/26/23 23:57:12 1265.8 -Model 09B 01/26/23 23:07:48 1169.38 -Model 10 01/26/23 23:07:48 1294.04

a Citations for PEP-FOLD Technology and Services:

Shen Y, Maupetit J, Derreumaux P, Tufféry P. Improved PEP-FOLD approach for peptide and miniprotein structure prediction J. Chem. Theor. Comput. 2014; 10:4745-4758

Thévenet P, Shen Y, Maupetit J, Guyon F, Derreumaux P, Tufféry P. PEP-FOLD: an updated de novo structure prediction server for both linear and disulfide bonded cyclic peptides. Nucleic Acids Res. 2012. 40, W288-293.

Maupetit J, Derreumaux P, Tufféry P. PEP-FOLD: an online resource for de novo peptide structure prediction. Nucleic Acids Res. 2009. 37(Web Server issue):W498-503. doi:10.1093/nar/gkp323 Maupetit J, Derreumaux P, Tuffery P.

A fast and accurate method for large-scale de novo peptide structure prediction.

J Comput Chem. 2010. 31-726-38.