Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• synthetic glycoproteins. Since the discovery of native chemical ligation (NCL) by Kent and co-workers, numerous efforts have been made to prepare challenging protein targets [39][40][41][42][43][44]. In the NCL method, a native amide bond is formed by coupling of a C-terminal thioester with the N-terminal

• Fmoc-SPPS followed by sequential NCL [51]. The N-glycopeptide fragment RNase 26–39 (17) was prepared with a thioester in the C-terminal and a thiazolidine protected cysteine at the N-terminus. The chemical ligation was performed by coupling of the N-glycopeptide thioester RNase 26–39 (17) and the

• RNase fragment 26–124 (20) to the thioester peptide fragment RNase 1-25 (21) was followed to give RNase fragment 1–124 (22). The formed RNase C protein was then folded by treatment with glutathione disulfide (GSSG) resulting in an active RNase C enzyme (23) (Scheme 3). Recently, the 111-amino-acid long

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• Claisen-type cyclization step to form the characteristic bicyclic ring structure of anatoxin while the growing chain is tethered to the AnaF ACP domain. Experimental evidence for this suggestion is currently lacking. Finally, the bicyclic thioester is suggested to be transferred to the polyketide synthase

• biosynthesis include a six-carbon carboxylic acid unit as starter moiety. In vitro studies revealed the activation of either hexanoic, hexenoic or hexynoic acids at the JamA enzyme, whereas bromination clearly succeeded thioester formation [43]. Curacin A Curacin A (9) was originally isolated from a Lyngbya

• halogenation domain, although this could not be expected from the structure of curacin A. In vitro studies revealed that indeed cyclopropyl ring formation is preceded by a halogenation step (Figure 6B) [42]. The Cur ECH2 was found to catalyze the formation of a α,β-enoyl thioester, which is in contrast to the

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33