Conformational analysis and aqueous hydration studies of model peptides for the adhesive protein of the mussel, Mytilus edulis L.
Conformations of model peptides of the adhesive protein of the mussel, Mytilus edulis L were investigated using molecular mechanics. The protein structure was represented as the repeat of a 10-residue unit. This decamer, and di- and tri-decamers of it, were considered in the modeling. Incorporation of the unusual dopamine residue in the decamer repeat may be explained by its hydrogen bond forming ability via its 3-OH group to a proline carbonyl oxygen. This bond contributes to maintaining a double reverse beta-turn structure in the decamer. This conformation was found more stable than 3(1) and alpha helical conformations. Adjacent reverse beta-turn structures are connected by short segments (2 to 3 residues) having little conformational preference. Thus, the overall protein can possess a significant random nature, yet have a highly ordered embedded conformational component. Hydrophilic character is in line with the larger number of OH groups on the phenyl ring for residue 9 (the site of the Dopa residue). The dehydration free energy of the (3-OH)-Phe as compared to the Dopa derivative is less by 1.4 kcal per decamer unit. This amounts to more than 100 kcal energy gain in the dehydration process for the total protein.
Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago.
P I
PI
Nagy
H C
HC
Patel
W
W
Dreyer
A J
AJ
Hopfinger
D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia; D004298:Dopamine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D014867:Water
D011506:Proteins; C037403:adhesive protein, mussel; D014867:Water; D004298:Dopamine