生物化学技术

Site-specific modification of glycoproteins has wide application in both biochemical and biophysical studies. This method describes the conjugation of synthetic molecules to the N-terminus of a glycoprotein fragment, viz., human immunoglobulin G subclass 1 fragment crystal ...

Conjugates of bacterial polysaccharides covalently bound to a carrier protein are among licensed human vaccines. Immunization of adults and children with these vaccines results in induction of saccharide-specific antibodies composed mainly of the IgG class. Depending on the ch ...

Carbohydrates are important molecular targets in the development of vaccines against cancer, viral and bacterial infections, and many other diseases. However, carbohydrates are usually poorly immunogenic and cannot induce a T cell-dependent immune response that is necessary f ...

Disadvantages of classical vaccines, such as the risk of an autoimmune reaction, might be overcome by using a subunit vaccine containing the minimal microbial components necessary to stimulate appropriate immune responses. However, vaccines based on minimal epitopes suffer from p ...

This chapter presents a technique that employs mutant glycosyltransferase enzymes for the site-specific bioconjugation of biomolecules via a glycan moiety to facilitate the development of a targeted drug delivery system. The target specificity of this methodology is based on uni ...

Liposome surface functionalization facilitates the enormous potential applications of liposomes, such as stabilizing and targeting carrier systems for delivering active molecules in biomedical research and applications. Cell surface carbohydrates have been an attra ...

DNA-polymer conjugates have been recognized as versatile functional materials in many different fields ranging from nanotechnology to diagnostics and biomedicine. They combine the favorable properties of nucleic acids and synthetic polymers. Moreover, joining both struc ...

Oligonucleotide–peptide conjugates have attracted considerable interest especially for biomedical uses. In the first part of this chapter, we describe protocols for the stepwise synthesis of oligonucleotides carrying peptide sequences at the 3′-end on a single support. The res ...

Unaided cellular uptake of RNA interference agents such as antisense oligonucleotides and siRNA is extremely poor, and in vivo bioavailability is also limited. Thus, effective delivery strategies for such potential drugs are in high demand. Recently, a novel approach using a class of sho ...

Site-specific and chemoselective labeling of DNA is still a difficult task. The Staudinger ligation is a bioorthogonal reaction between azides and phosphines that requires no catalyst to proceed, allowing for mild reaction conditions. The reaction may be extended for site-specific ...

A glycomimetic oligonucleotide conjugate bearing four galactose residues on a mannose core is �synthesized using oligonucleotide solid-phase synthesis and Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, or “click” chemistry). To achieve this purpose, new ...

Incorporating synthetic probes site-specifically into proteins is of central interest in several areas of biotechnology and protein chemistry. Bioconjugation techniques provide a simple and effective means of chemically modifying a protein. In particular, covalent chemi ...

PEGylation, the covalent linking of PEG chains, has become the leading drug delivery approach for proteins. This technique initiated its first steps almost 40 years ago, and since then, a variety of methods and strategies for protein–polymer coupling have been devised. PEGylation can give a n ...

Polyamine polymers are among the commonest polymers used in biomedicine. Among polyamine �polymers, polyethylenimine (PEI) may be used as an efficient delivery vehicle for nucleic acids (DNA, RNA, etc.) or employed as a versatile imaging probe in vivo. In this chapter, the preparation of var ...

Transglutaminase (TGase) is an enzyme that catalyzes the post-translational covalent cross-linking of Gln- and Lys-containing peptides and/or proteins according to its substrate specificity. We have recently designed a variety of Gln-donor fluorescent substrates of microb ...

The synthesis of molecular conjugates through chemoselective ligations represents a very convenient strategy to prepare complex macromolecules with diverse functional elements. Herein, we describe chemical methods based on the preparation of chemoselectively addres ...

X-ray crystallography has been particularly important in the study of the enzyme nitrogenase, providing researchers with high-resolution structural models that have been essential to studying the enzyme’s unique metal clusters and nucleotide-binding modes and protein inte ...

Nitrogenase-like dark operative protochlorophyllide oxidoreductase (DPOR) is involved in the biosynthesis of chlorophylls and bacteriochlorophylls in gymnosperms, ferns, algae, and photosynthetic bacteria. During protochlorophyllide (Pchlide) reduction, the ...

Steady-state assays of nitrogenases share at least five requirements: an anaerobic environment, a consistent source of magnesium adenosine triphosphate (MgATP), a suitable source of reductant, a buffer system compatible with the product-quantification protocol to be used, and t ...

Nitrogenase is one of the most complex enzymes known to date. The extensively studied molybdenum nitrogenase consists of two protein components and three metal centers that are critical for nitrogenase activity. The inherent complexity of this enzyme system, which is further compoun ...