Hinge-peptide

FIGURE 2. A Subunit of S. cerevisiae Flavocytochrome bj The protein is shown as a ribbon diagram with the heme and flavin cofactors in a stick representation. The two domains are clearly delineated. Cyt, cytochrome domain Flav, flavin domain H, interdomain hinge peptide C, C-terminal tail. 

B. Hinge-Peptide Based Fully Synthetic Immunogens... 

Fig. 17. Synthesis of the hinge-peptide 225-232/225 -232 in parallel and antiparallel alignment by selective disulfide bridging methods.

In order to confirm the protein subdomain-like character of the hinge-peptide 225-232/225 -232 its preferred conformation was analyzed by CD and. v spectroscopy (88,236) and compared to Its 3D-structure In the native protein. ns mentioned above formation of the correct disulfide pattern In this protein fragment was expected to occur as consequence of a thermodynamically highly favored conformation. The CD spectra of the monomeric bls-cysteinyl-compound H-Thr(tBu)-Cys-Pro-Pro-Cys-Pro-Ala-Pro-OH. of the dimeric mono-cystlnyl-... 

Because of the high stability of the hinge-peptide structure and Its rigidity In the core portion, but flexibility of the exocyclic parts, this structural unit fulfils the requirements of a template for the construction of synthetic mlniprotelns as potential immunogens (206,207). 

Synthesis and Conformation of Hinge-Peptide/ Gastrin Chimeras... 

The main task of our model studies was to assess the biological and conformational properties of various hinge-peptide/gastrin constructs and to correlate these with the specificity of the antibody responses if an immune response ccould be elicited by such simple chimeric compounds. 

As outlined in Fig. 21, the hinge-peptide compounds extended N-terminally with... 

Fig. 21. Scheme for the selective synthesis of the [Nle15]-gastrin-l5-l 7j/hinge-peptide compound in parallel and antiparallel alignment and of the parallel compound by air-oxidation. 

Fig. 22. Scheme for the synthesis of hinge-peptide/[NleI5]-gastrin-[2-17] in parallel alignment. 

Fig. 23. Synthetic routeforbig-gastrin-[l-14 /hinge-peptide/[Nle15]-gastrin-[2-17].

Fig. 24. CD spectra of the hinge-peptide (curve 1), [Nle15]-gastrin-[2-l 7] (curve 2) and hinge-peptide/[Nle15]-gastrin-(2-l 7) (curve 3) in aqueous solution. The computed spectrum (curve 4) was obtained by addition of the CD curves 1 and 2. The CD spectrum of hinge-peptide/[Nle15 -gastrin-[5-17] is almost superimposable to that of curve 3.

The extension of the double-chain hinge-peptide 225-232/225 -232 at the two C-termlni with the [Nle15]-gastrin sequences 5-17 and 2-17 leads to CD spectra (Fig. 24) In aqueous solution which are practically Identical to those computed by... 

Fig. 25. Comparison of the CD spectra of hinge-peptide/[Nle15]-gastrln-[2-17] (curve 1) and hinge-peptide/[N el5]-gastrln-l5-l 7] (curve 2) in 9596 TFE.

Fig. 26. Stereoview of the starting conformation of hinge-peptide/[Nle15]-gastrin-[2-171 (top) as modelled from the conformational states of the component parts in TFE and after 50 ps simulation (bottom).

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