Synthesis of cyclopentapeptides and cycloheptapeptides by DEPBT and the influence of some factors on cyclization.
Three cyclic peptides - cyclo(GlyAlaTyrLeuAla), cyclo(GlyProTyrLeuAla) and cyclo(GlyTyrGlyGlyProPhePro) - isolated and identified from medicinal herbs were chosen as model cyclic peptides to study the influence of the linear precursors and coupling reagents on cyclization. The 17 linear precursors of these three cyclic peptides were synthesized and cyclized using 3-(diethoxyphosphoryloxy)-(1-3)-benzotriazin-4 (3H)-one (DEPBT) as the major coupling reagent. The present work shows that: (i) the effects of linear peptide precursors on the cyclization are complex but some guidelines for choosing suitable precursor for cyclization could be considered; and (ii) DEPBT results in a higher cyclization yield compared with other coupling reagents. In addition, it was confirmed that peptides containing alternating D and L residues favor cyclization.
Tang
Yan-chun
YC
Structural Biology and Biochemistry, Hospital for Sick Children, Toronto, Ontario, Canada.
Xie
Hai-Bo
HB
Tian
Gui-ling
GL
Ye
Yun-hua
YH
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002942:Circular Dichroism; D003500:Cyclization; D010755:Organophosphates / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000032:analysis / Q000138:chemical synthesis*; D011487:Protein Conformation; D011498:Protein Precursors / Q000737:chemistry; D014227:Triazines / Q000737:chemistry*
C410327:3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one; D000596:Amino Acids; D010755:Organophosphates; D010456:Peptides, Cyclic; D011498:Protein Precursors; D014227:Triazines