Amino acids, conformationally glucagon

Deduce the probable conformation of porcine glucagon with the following sequence (construct initial structure in a helix from amino acids with HyperChem which lists residue ID in PDB file) by geometry optimization until the difference in energies between the successive steps is less than 1.0 kcal/mol or rms gradient of 0.1 kcal/(mol-A) ... 

Glucagon is a polypeptide containing 29 amino acids and no stabilizing disulfide bonds (Behrens and Bromer, 1958). The hormone was crystallized shortly after its discovery and isolation and was found to form rhombic dodecahedra with cubic symmetry and 12 molecules per unit cell (King, 1965). The conformation of the hormone in crystals as determined by X-ray analysis (Sasaki et a/., 1975) is shown in Fig. 9. The molecule is a helical... 

The conclusion that a peptide such as bradykinin consisting of nine amino acids does not have a preferred conformation but that a well defined geometry develops from a certain chain length on (secretin contains twenty-seven amino acids, glucagon with fairly similar sequence and somewhat similar spectra twenty-nine amino acids), would be attractive but is not well founded. Examination of the ORD and CD spectra of the intestinal hormone cholecystokinin-pancreozymin (CCK), a single chain peptide of 33 amino acids, gives no evidence for structural rigidity which would express itself in spectra similar to those of helical molecules. 

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