Chitin binding by CBM14

Using NMR to get the solution structure of CBM14, we gained insight into secondary structure elements and intramolecular interactions with assigned NOEs.

Results show that both Trp465 and Asn466 are affected when CBM14 interacts with both (GlcNAc)3 and β-chitin, that the binding interactions are weak, and that CBM14 displays a slightly higher affinity toward β-chitin.

Read the paper here: doi:10.1021/acsomega.9b030🔗

Chemoenzymatic synthesis of glycoconjugates

This is a simple and highly specific approach to produce oxime-based glycoconjugates from LPMO-functionalized oligosaccharides. The products are evaluated by HPLC, mass spectrometry and NMR. Furthermore, we demonstrate potential biodegradability of these glycoconjugates using selective enzymes.

Read the paper here: doi:10.1038/s41598-020-69951-7🔗

Characterization of three alginate-modifying enzymes

The three A. chroococcum genes (AcalgE1, AcalgE2 and AcalgE3) were recombinantly expressed in E. coli and the gene products were partially purified.

AcAlgE1 displayed epimerase activity and was able to introduce long G-blocks in the alginate substrate, preferentially by attacking M residues next to pre-existing G residues. AcAlgE2 and AcAlgE3 were found to display lyase activities with a substrate preference toward M-alginate.

Read the paper here: doi:10.1038/s41598-020-68789-3🔗

Alginate conjugates to treat MDR bacterial infections

We generated and characterise dalginate oligosaccharide (“OligoG”)–polymyxin (polymyxin B and E (colistin)) conjugates to improve the effectiveness of colistin.

Bi-functional OligoG–polymyxin conjugates were shown to have potential therapeutic benefits in the treatment of multidrug-resistant (MDR) Gram-negative bacterial infections, directly reducing toxicity whilst retaining antimicrobial and antibiofilm activities.

Read the paper here: doi:10.3390/pharmaceutics12111080🔗

NMR structures and biological activity of two lasso peptides

We solved the NMR structures of two lasso peptides from Amycolatopsis. By themselves, they have no effect on cancer cells. Together, they increase their proliferation and sensitivity to DOX. Therefore, we also investigated the complex formation by NMR.

Read the paper here: doi:10.1016/j.isci.2020.101785🔗

Characterization of five sulfated fucoidans

We used ion-exchange chromatography to purify different fucoidans and found a high structural diversity between fucoidans.

By monomer composition, linkage analysis and NMR characterization, we identified galacturonic acid, glucuronic acid and O-acetylation as new structural features of certain fucoidans and provided a novel structure of fucoidan with α-1,3-linked fucose backbone and β-1,6 and β-1,3 galactose branches.

Read the paper here: doi:10.1093/glycob/cwaa064🔗

Rational design of an alginate epimerase

We rationally designed new hybrid mannuronan C-5 epimerases constituting the A-module from AlgE6 and the R-module from AlgE4. This led to a better understanding of the molecular mechanism determining differences in MG- and GG-block-forming properties of the enzymes.

A long loop with either tyrosine or phenylalanine extruding from the β-helix of the enzyme proved essential in defining the final alginate block structure, probably by affecting substrate binding.

Read the paper here: doi:10.1021/acsomega.9b04490🔗