Development of orthogonally protected hypusine for solid-phase peptide synthesis

Area of Science:

• Biochemistry
• Organic Chemistry
• Peptide Synthesis

Background:

• Hypusine is a rare amino acid crucial for the function of certain proteins, including translation initiation factors.
• Previous methods for synthesizing hypusinated peptides faced challenges in protecting group compatibility and synthetic efficiency.

Purpose of the Study:

• To develop a novel, orthogonally protected hypusine reagent for streamlined solid-phase peptide synthesis.
• To ensure compatibility of the reagent with established Fmoc/t-Bu chemistry for broad applicability.

Main Methods:

• The reagent was synthesized in a seven-step process starting from Cbz-Lys-OBzl and (R)-3-hydroxypyrrolidin-2-one.
• Orthogonal protection strategies were employed, utilizing Boc and t-Bu protecting groups for the hypusine side chain.
• The synthesized reagent was utilized in solid-phase peptide synthesis employing the Fmoc/t-Bu strategy.

Main Results:

• A novel orthogonally protected hypusine reagent was successfully synthesized with an overall yield of 27%.
• The Boc and t-Bu side-chain protecting groups demonstrated full compatibility with standard Fmoc chemistry.
• The protecting groups were readily removable during the final peptide cleavage step.
• The reagent's utility was confirmed through the successful solid-phase synthesis of hypusinated peptides.

Conclusions:

• The developed hypusine reagent provides a robust and efficient tool for incorporating hypusine into peptides.
• This advancement simplifies the synthesis of complex peptides containing hypusine, facilitating further research into hypusine-containing proteins.