Magnetization of active inclusion bodies: comparison with centrifugation in repetitive biotransformations.

BACKGROUND: Physiological aggregation of a recombinant enzyme into enzymatically active inclusion bodies could be an excellent strategy to obtain immobilized enzymes for industrial biotransformation processes. However, it is not convenient to recycle "gelatinous masses" of protein inclusion bodies from one reaction cycle to another, as high centrifugation forces are needed in large volumes. The magnetization of inclusion bodies is a smart solution for large-scale applications, enabling an easier separation process using a magnetic field. RESULTS: Magnetically modified inclusion bodies of UDP-glucose pyrophosphorylase were recycled 50 times, in comparison, inclusion bodies of the same enzyme were inactivated during ten reaction cycles if they were recycled by centrifugation. Inclusion bodies of sialic acid aldolase also showed good performance and operational stability after the magnetization procedure. CONCLUSIONS: It is demonstrated here that inclusion bodies can be easily magnetically modified by magnetic iron oxide particles prepared by microwave-assisted synthesis from ferrous sulphate. The magnetic particles stabilize the repetitive use of the inclusion bodies .

A semi-multifunctional sialyltransferase from Bibersteinia trehalosi and its comparison to the Pasteurella multocida ST1 mutants.

Sialic acids are well known for their crucial roles in many physiological and pathological processes. Improvement in the efficacy of protein drugs, an increase in the anti-inflammatory activity of intravenous immunoglobulin, preparation of infant milk and the diagnosis of diseases are examples of why there is a need for efficient in vitro sialylation. Sialyltransferases are crucial enzymes for the synthesis of sialo-oligosaccharides. Here, we introduce a new α2,3-sialyltransferase from bacteria Bibersteinia trehalosi (BtST1), which is homological to sialyltransferase from Pasteurella multocida (PmST1), Pasteurella dagmatis (PdST1) and Haemophilus ducreyi (Hd0053). BtST1 is active in a wide pH range and shows considerable acceptor flexibility. Very good specific activities have been detected with lactose and LacNAc as acceptors, and these activities were comparable to those of efficient multifunctional PmST1 and higher than PdST1, Hd0053 and also PmST1 M144D which was constructed to decrease the high sialidase activity of PmST1. Testing of PmST1 mutant forms revealed that mutations that included S143 caused only the restriction of sialyltransferase activity, whereas mutations including G142 resulted in the loss of activity with lactose. BtST1 possesses only low sialidase and trans-sialidase activities that are comparable to mutant PmST1 M144D, which are detected only in the presence of CMP. The combination of large acceptor flexibility, high activity for lactose and LacNAc and naturally low sialidase activity make BtST1 an attractive enzyme for biotechnological applications.

Protein-RNA and protein-glycan recognitions in light of amino acid codes.

BACKGROUND: RNA-binding proteins, in cooperation with non-coding RNAs, play important roles in post-transcriptional regulation. Non-coding micro-RNAs control information flow from the genome to the glycome by interacting with glycan-synthesis enzymes. Glycan-binding proteins read the cell surface and cytoplasmic glycome and transfer signals back to the nucleus. The profiling of the protein-RNA and protein-glycan interactomes is of significant medicinal importance. SCOPE OF REVIEW: This review discusses the state-of-the-art research in the protein-RNA and protein-glycan recognition fields and proposes the application of amino acid codes in profiling and programming the interactomes. MAJOR CONCLUSIONS: The deciphered PUF-RNA and PPR-RNA amino acid recognition codes can be explained by the protein-RNA amino acid recognition hypothesis based on the genetic code. The tripartite amino acid code is also involved in protein-glycan interactions. At present, the results indicate that a system of four codons ("gnc", where n=g - guanine, c - cytosine, u - uracil or a - adenine) and four amino acids (G - glycine, A - alanine, V - valine, D - aspartic acid) could be the original genetic code that imprinted "rules" into both recognition processes. GENERAL SIGNIFICANCE: Amino acid recognition codes have provocative potential in the profiling and programming of the protein-RNA and protein-glycan interactomes. The profiling and even programming of the interactomes will play significant roles in diagnostics and the development of therapeutic procedures against cancer and neurodegenerative, developmental and other diseases.

Bacterial inclusion bodies as potential synthetic devices for pathogen recognition and a therapeutic substance release.

BACKGROUND: Adhesins of pathogens recognise the glycans on the host cell and mediate adherence. They are also crucial for determining the tissue preferences of pathogens. Currently, glyco-nanomaterials provide potential tool for antimicrobial therapy. We demonstrate that properly glyco-tailored inclusion bodies can specifically bind pathogen adhesins and release therapeutic substances. RESULTS: In this paper, we describe the preparation of tailored inclusion bodies via the conjugation of indicator protein aggregated to form inclusion bodies with soluble proteins. Whereas the indicator protein represents a remedy, the soluble proteins play a role in pathogen recognition. For conjugation, glutaraldehyde was used as linker. The treatment of conjugates with polar lysine, which was used to inactivate the residual glutaraldehyde, inhibited unwanted hydrophobic interactions between inclusion bodies. The tailored inclusion bodies specifically interacted with the SabA adhesin from Helicobacter pylori aggregated to form inclusion bodies that were bound to the sialic acids decorating the surface of human erythrocytes. We also tested the release of indicator proteins from the inclusion bodies using sortase A and Ssp DNAB intein self-cleaving modules, respectively. Sortase A released proteins in a relatively short period of time, whereas the intein cleavage took several weeks. CONCLUSIONS: The tailored inclusion bodies are promising "nanopills" for biomedical applications. They are able to specifically target the pathogen, while a self-cleaving module releases a soluble remedy. Various self-cleaving modules can be enabled to achieve the diverse pace of remedy release.