Avian pancreatic polypeptide fragments refold to native aPP conformation when combined in solution: a CD and VCD study.
An equimolar mixture of avian pancreatic polypeptide (aPP) fragments aPP(1-11)-NH2 and Ac-aPP(12-36) had an electronic circular dichroism (ECD) spectrum that was similar to that of whole aPP in H2O and even more so in 30% (v/v) trifluoroethanol (TFE) in 15 mM Na2HPO4, but was different from the sum of the spectra of the individual fragments. The vibrational circular dichroism (VCD) spectrum of the combined fragments in 30% (v/v) TFE in 15 mM Na2HPO4 in D2O was also similar to that of the intact aPP and unlike the sum of the VCD spectra of the fragments. The interaction of these fragments is thus sufficient to support the conformation of whole aPP. This study demonstrates that VCD, in combination with ECD, is useful for the study of protein-protein interactions.
Copps
Jeffrey
J
Department of Biomedical Sciences, Creighton University Medical Center, Omaha, Nebraska, USA.
Murphy
Richard F
RF
Lovas
Sándor
S
D000595:Amino Acid Sequence; D000818:Animals; D001704:Biopolymers / Q000737:chemistry; D002942:Circular Dichroism / Q000379:methods; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010191:Pancreatic Polypeptide / Q000138:chemical synthesis / Q000737:chemistry*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D012996:Solutions
D001704:Biopolymers; D010446:Peptide Fragments; D012996:Solutions; C009725:pancreatic polypeptide, avian; D010191:Pancreatic Polypeptide