Formation of AAB-Type Collagen Heterotrimers from Designed Cationic and Aromatic Collagen-Mimetic Peptides: Evaluation of the C-Terminal Cation-π Interactions.
Most of natural collagens are heterotrimers composed of two (AAB) or three (ABC) different peptide chains, and thus heterotrimeric constructs are preferable to mimic natural collagens. Exploring the forces to assemble synthetic collagen-mimetic peptides (CMPs) into heterotrimers has been an attractive topic in preparing collagen-related biomaterials. Here we designed and synthesized two cationic CMPs (CR and CK) in which multiple Arg or Lys residues are installed in their C-terminal region, and one aromatic CMP (CF) whose C-terminal end contains multiple Phe residues. Circular dichroism and NMR spectroscopy showed that AAB-type heterotrimers could form in both CR-CF and CK-CF mixtures, suggesting that the C-terminal cation-π interactions between cationic and aromatic residues could serve as a nucleation force and substantially promote the folding of heterotrimers. In particular, only one major heterotrimeric fold was found in each mixture. For CR-CF mixtures, either the heterotrimer with two CR chains and one CF chain or that with one CR chain and two CF chains could form, depending on the molar ratios of CR to CF in solution. By contrast, in CK-CF mixtures only the heterotrimer consisting of two CK chains and one CF chain was found in solution even increasing the ratio of CF, implying that the heterotrimer composed of one CK chain and two CF chains is highly unstable. Additionally, differential scanning calorimetry analysis showed that the folding of these heterotrimers is governed by entropic effects. Together, our results provide a new design to prepare AAB-type collagen heterotrimers and reveal new insights into their folding thermodynamics.
Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University , 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC.
Chu-Harn
CH
Chiang
Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University , 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC.
Yi-Hsuan
YH
Fu
Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University , 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC.
Jia-Cherng
0000-0002-9936-5338
JC
Horng
D040761:Biomimetic Materials / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002412:Cations / Q000737:chemistry*; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D013816:Thermodynamics
D002412:Cations; D010455:Peptides; D003094:Collagen