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Tillib S.V.,Russian Academy of Sciences | Vyatchanin A.S.,Russian Academy of Sciences | Muyldermans S.,Vrije Universiteit Brussel | Muyldermans S.,Vlaams Interuniversitair Instituut voor Biotechnologie
Biochemistry (Moscow) | Year: 2014

In this work, IgG content and structures of antigen-binding domains and hinge regions of different IgG subtypes of Camelus bactrianus were analyzed in detail for the first time. Our data demonstrate that C. bactrianus contains a very large amount of heavy chain-only antibodies that can be used as a source of VHH domain-containing molecules. Despite some minor sequence differences identified in this study, C. bactrianus VHH domains possess principally the same unique features as those of C. dromedarius and the llama. These features are important for developing an efficient phage display-based anti- body selection technology. We conclude that C. bactrianus is a very suitable animal to raise an immune response that serves as a source to identify antigen-specific VHHs selected after phage display. © 2014 Pleiades Publishing, Ltd. Source


Patent
Vlaams Interuniversitair Instituut Voor Biotechnologie | Date: 2011-04-01

The present invention relates to functional heavy chain antibodies, functional single domain heavy chain antibodies, functional VH domains, or functional fragments thereof comprising an amino acid which is neither a charged amino acid nor a C at position 45, and comprising an amino acid at position 103 independently chosen from the group consisting of R, G, K, S, Q, L, and P, and optionally an amino acid at position 108 independently chosen from the group consisting of Q, L and R, said positions determined according to the Kabat numbering.


Patent
Vlaams Interuniversitair Instituut Voor Biotechnologie | Date: 2011-08-12

The present invention relates to functional heavy chain antibodies, functional single domain heavy chain antibodies, functional VH domains, or functional fragments thereof comprising an amino acid which is neither a charged amino acid nor a C at position 45, and comprising an amino acid at position 103 independently chosen from the group consisting of R, G, K, S, Q, L, and P, and optionally an amino acid at position 108 independently chosen from the group consisting of Q, L and R, said positions determined according to the Kabat numbering.


De Genst E.,University of Cambridge | Chan P.-H.,University of Cambridge | Chan P.-H.,Hong Kong Polytechnic University | Pardon E.,Vlaams Interuniversitair Instituut voor Biotechnologie | And 16 more authors.
Journal of Physical Chemistry B | Year: 2013

We report the effects of the interaction of two camelid antibody fragments, generally called nanobodies, namely cAb-HuL5 and a stabilized and more aggregation-resistant variant cAb-HuL5G obtained by protein engineering, on the properties of two amyloidogenic variants of human lysozyme, I56T and D67H, whose deposition in vital organs including the liver, kidney, and spleen is associated with a familial non-neuropathic systemic amyloidosis. Both NMR spectroscopy and X-ray crystallographic studies reveal that cAb-HuL5 binds to the α-domain, one of the two lobes of the native lysozyme structure. The binding of cAb-HuL5/cAb-HuL5G strongly inhibits fibril formation by the amyloidogenic variants; it does not, however, suppress the locally transient cooperative unfolding transitions, characteristic of these variants, in which the β-domain and the C-helix unfold and which represents key early intermediate species in the formation of amyloid fibrils. Therefore, unlike two other nanobodies previously described, cAb-HuL5/cAb-HuL5G does not inhibit fibril formation via the restoration of the global cooperativity of the native structure of the lysozyme variants to that characteristic of the wild-type protein. Instead, it inhibits a subsequent step in the assembly of the fibrils, involving the unfolding and structural reorganization of the α-domain. These results show that nanobodies can protect against the formation of pathogenic aggregates at different stages in the structural transition of a protein from the soluble native state into amyloid fibrils, illustrating their value as structural probes to study the molecular mechanisms of amyloid fibril formation. Combined with their amenability to protein engineering techniques to improve their stability and solubility, these findings support the suggestion that nanobodies can potentially be developed as therapeutics to combat protein misfolding diseases. © 2013 American Chemical Society. Source


Martinez-Rodriguez S.,University of Almeria | Garcia-Pino A.,Vrije Universiteit Brussel | Garcia-Pino A.,Vlaams Interuniversitair Instituut voor Biotechnologie | Heras-Vazquez F.J.L.,University of Almeria | And 6 more authors.
Journal of Bacteriology | Year: 2012

N-Carbamoyl-L-amino acid amidohydrolases (L-carbamoylases) are important industrial enzymes used in kinetic resolution of racemic mixtures of N-carbamoyl-amino acids due to their strict enantiospecificity. In this work, we report the first L-carbamoylase structure belonging to Geobacillus stearothermophilus CECT43 (BsLcar), at a resolution of 2.7 Å. Structural analysis of BsLcar and several members of the peptidase M20/M25/M40 family confirmed the expected conserved residues at the active site in this family, and site-directed mutagenesis revealed their relevance to substrate binding. We also found an unexpectedly conserved arginine residue (Arg234 in BsLcar), proven to be critical for dimerization of the enzyme. The mutation of this sole residue resulted in a total loss of activity and prevented the formation of the dimer in BsLcar. Comparative studies revealed that the dimerization domain of the peptidase M20/M25/M40 family is a "small-molecule binding domain," allowing further evolutionary considerations for this enzyme family. © 2012, American Society for Microbiology. Source

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