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Jan C M van Hest

Publications and source records attributed to Jan C M van Hest.

10 recordsLinked to original sources
PubMed2006

Stereoselective incorporation of an unsaturated isoleucine analogue into a protein expressed in E. coli.

The unsaturated amino acid 2-amino-3-methyl-4-pentenoic acid (E-Ile) was prepared in the form of its (2S,3S),(2R,3R) and (2S,3R),(2R,3S) stereoisomeric pairs. The translational activities of SS-E-Ile and SR-E-Ile were assessed in an E. coli strain rendered auxotrophic for isoleucine. SS-E-Ile was incorporated into the test protein mouse dihydrofolate reductase (mDHFR) in place of isoleucine at a rate of up to 72 %; SR-E-Ile yielded no conclusive evidence for incorporation. ATP/PPi exchange assays indicated that SS-E-Ile was activated by the isoleucyl-tRNA synthetase at a rate comparable to that characteristic of isoleucine; SR-E-Ile was activated approximately 100-times more slowly than SS-E-Ile.

Animals↗
PubMed2006

Solid-phase synthesis of C-terminally modified peptides.

In this paper, a straightforward and generic protocol is presented to label the C-terminus of a peptide with any desired moiety that is functionalized with a primary amine. Amine-functional molecules included are polymers (useful for hybrid polymers), long alkyl chains (used in peptide amphiphiles and stabilization of peptides), propargyl amine and azido propyl-amine (desirable for 'click' chemistry), dansyl amine (fluorescent labeling of peptides) and crown ethers (peptide switches/hybrids). In the first part of the procedure, the primary amine is attached to an aldehyde-functional resin via reductive amination. To the secondary amine that is produced, an amino acid sequence is coupled via a standard solid-phase peptide synthesis protocol. Since one procedure can be applied for any given amine-functional moiety, a robust method for C-terminal peptide labeling is obtained.

Aldehydes↗
PubMed2005

Tuning secondary structure and self-assembly of amphiphilic peptides.

Self-assembly is one of nature's mechanisms by which higher order structures are obtained. Two of the main driving forces for self-assembly, hydrophobic interactions and hydrogen bonding, are both present within amphiphilic peptides. Here, it is demonstrated how the intricately interconnected folding and assembly behavior of an N-terminally acylated peptide, with the sequence GANPNAAG, has been tuned by varying its hydrophobic tail and thermal history. The change in interplay between hydrophobic forces and peptide folding allowed the occurrence of different types of aggregation, from soluble peptides with a random coil conformation to aggregated peptides arranged in a beta-sheet assembly, which form helically twisted bilayer ribbons.

Acylation↗
PubMed2004

Solid phase synthesis of biohybrid block copolymers.

A new versatile route to synthesise biohybrid block copolymers is presented in which an amine terminated polymer is attached to an aldehyde functionalised resin, from which in subsequent steps the desired peptide can be grown using standard procedures.

Aldehydes↗
PubMedDate not supplied

Beta-sheet side chain polymers synthesized by atom-transfer radical polymerization.

Silks are a widely studied class of naturally occurring structural proteins. Dragline spider silk, in particular, is considered to be nature's high-performance material due to its remarkable combination of strength and toughness. These mechanical properties stem from the protein secondary structure, a combination of well-defined beta-sheets in a less well-defined glycine-rich matrix. The translation of this structure into a synthetic polymer was the aim of this investigation. To achieve this, a peptide-based monomer containing the sequence alanine-glycine-alanine-glycine, a well-known beta-sheet-forming sequence found in silk, was synthesized. Using atom-transfer radical polymerization and a bifunctional initiator, a well-defined peptide-based polymer was prepared. This was then used as the macroinitiator for the polymerization of methyl methacrylate. The resulting well-defined triblock copolymer was analyzed using IR spectroscopy, which clearly showed beta-sheet secondary structure had been introduced.

Dipeptides↗