The part of a long beta hairpin from the scrapie form of the human prion protein is reconstructed in the synthetic CC36 protein.
Mechanisms of beta sheet formation by the human prion protein are not clear yet. In this work, we clarified the role of the region containing C-half of the second helix and N-half of the third helix of that protein in the process of alpha helix to beta sheet transition. Solid phase automatic synthesis of the original peptide (CC36: Cys179-Cys214) failed because of the beta hairpin formation in the region 206-MERVVEQMC-214 with a high beta strand potential. Using Met206Arg and Val210Arg substitutions, we increased the probability of alpha helix formation by that sequence. After that modification, the complete CC36 peptide with disulfide bond has been synthesized. Modified peptide has been studied by circular dichroism (CD) and fluorescence spectrography. According to the CD spectra analysis, the CC36 peptide contains 37% of residues in beta sheet and just 15% in helix. Thermal analysis under the control of CD shows that the secondary structure content of the peptide is stable from 5°C to 80°C. Dissociation of oligomers of the CC36 peptide finishes at 37°C according to the fluorescence analysis. The CC36 peptide is able to bind Mn(2+) cations, which causes small temperature-associated structural shifts at concentrations of 2 - 10·10(-6) M. Predicted beta hairpin of the CC36 peptide (two beta strands are: 184-IKQHTVT-190 and 197-TETDVKM-205) should be the part of a longer beta hairpin from the scrapie form of the prion protein (PrPSc). Analogs of the CC36 peptide may be considered as antigens for the future development of a vaccine against PrPSc. Proteins 2016; 84:1462-1479. © 2016 Wiley Periodicals, Inc.
Department of General Chemistry, Belarusian State Medical University, Dzerzinskogo, 83, Minsk, Belarus. vvkhrustalev@mail.ru.
Vladislav Victorovich
VV
Khrustalev
Laboratory of Cellular Technologies, Institute of Physiology of the National Academy of Sciences of Belarus, Academicheskaya, 28, Minsk, Belarus.
Tatyana Aleksandrovna
TA
Khrustaleva
Department of Crystallography Center of Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego, 12/14, Poznan, Poland.
Kamil
K
Szpotkowski
Department of General Chemistry, Belarusian State Medical University, Dzerzinskogo, 83, Minsk, Belarus.
Victor Vitoldovich
VV
Poboinev
Department of General Chemistry, Belarusian State Medical University, Dzerzinskogo, 83, Minsk, Belarus.
Katsiaryna Yurieuna
KY
Kakhanouskaya
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D002413:Cations, Divalent; D006801:Humans; D008345:Manganese / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D018620:PrPSc Proteins / Q000737:chemistry*; D011485:Protein Binding; D000072417:Protein Domains; D055550:Protein Stability; D017433:Protein Structure, Secondary; D013816:Thermodynamics
D002413:Cations, Divalent; D010455:Peptides; D018620:PrPSc Proteins; D008345:Manganese
circular dichroism; manganese; prion protein; secondary structure; synthetic peptide; tryptophan fluorescence