The tremendous therapeutic potential of peptides has not yet been realized, mainly due to their short in vivo half-life. While conjugation to macromolecules has been a mainstay approach for enhancing the half-life of proteins, the steric hindrance of macromolecules often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Here we report a new strategy for enhancing the in vivo half-life of peptides without compromising their potency. Our approach involves endowing peptides with a small-molecule that binds reversibly to the serum protein, transthyretin. Although there are few reversible albumin-binding molecules, we are unaware of designed small molecules that bind reversibly to other serum proteins and are used for half-life extension in vivo. We show here that our strategy was indeed effective in enhancing the half-life of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy.

Incorporation of a pH-sensitive conformational switch into a lipid structure enables a drastic conformational flip upon protonation that disrupts the liposome membrane and causes rapid release of cargo specifically in areas of increased acidity. pH-sensitive liposomes containing the amphiphile (1) with trans-2-morpholinocyclohexanol conformational switch, a phospholipid, and a PEG-lipid conjugate were constructed and characterized. The optimized composition—1/POPC/PEG-ceramide (50/4/5)—could be stored at 4 °C and pH 7.4 for up to 1.5 years, and was stable in blood serum in vitro after 48 h at 37 °C. Liposomes loaded with ANTS/DPX or methotrexate demonstrated an unusually quick content release (in a few seconds) at pH below 5.5, which was independent of inter-liposome contact. The pH-titration curve for the liposome leakage paralleled the curve for the acid-induced conformational flip of 1 studied by 1H-NMR. Freeze-fracture electron microscopy images showed budding and division of the bilayer at pH 5.5. A plausible mechanism of pH-sensitivity involves an acid-triggered conformational flip of 1, shortening of lipid tails, and membrane perturbations, which cause the content leakage. The methotrexate-loaded liposomes demonstrated much higher cytotoxicity in HeLa cells than the free drug indicating that they can serve as viable drug delivery systems.

A long-range glycosyl transfer reaction was observed in the collision-induced dissociation Fourier transform (CID FT) mass spectra of benzylamine-labeled and 9-aminofluorene-labeled lacto-N-fucopentaose I (LNFP I) and lacto-N-difucohexaose I (LNDFH I). The transfer reaction was observed for the protonated molecules but not for the sodiated molecules. The long-range glycosyl transfer reaction involved preferentially one of the two L-fucose units in labeled LNDFH I. CID experiments with labeled LNFP I and labeled LNFP II determined the fucose with the greatest propensity for migration. Further experiments were performed to determine the final destination of the migrating fucose. , and post-translational protein modification [6 -8]. Whereas the insight into the physical process of carbohydrate recognition is in its infancy, considerable progress has been made towards the quantitation and structural elucidation of biologically active oligosaccharides. NMR [9] yields structural information about oligosaccharides. Frequently, however, an inherent problem is the limited amount of sample causing NMR experiments to become time-consuming or impossible. The sensitivity and accuracy of mass spectrometry has made this technique the best choice for analysis of oligosaccharides [10,11]. Structural information can be derived from collision-induced dissociation (CID) [12][13][14][15][16][17][18][19][20] or from post-source decay (PSD) time-of-flight (TOF) experiments [21][22][23][24][25][26]. Fragmentation of glycosidic bonds provides information about the monosaccharide sequence and computer algorithms can extract sequence information from web-based catalogs of MS n spectra [27]. However, the assignment of anomeric configuration [28 -35] and linkage [18, 36 -38] within the oligosaccharide structure is not a trivial task. Glycosidase digestion [13, 39 -47] in conjunction with mass spectrometric analysis can be used to assign linkage and stereochemistry. In an alternative approach, CID-fragmentation patterns have been linked to structural motifs in the oligosaccharide (catalog library approach) [12].We recently reported on the use of more nucleophilic benzylogous amines, such as benzylamine and 9-aminofluorene, for the labeling of oligosaccharides and the experimental results of FT-MS experiments with the labeled oligosaccharides [48]. Detection of 5 pmol of 9-amino fluorene-labeled oligosaccharide was achieved with a photo diode array during HPLC separation. The label combines low cost with good nucleophilicity and ease of introduction. The behavior of oligosaccharides derivatized with benzylogous amines such as benzylamine in CID experiments has not been reported, although data obtained from PSD matrix-assisted laser desorption/ionization (MALDI)-TOF experiments have been published [25,49].In this paper, we discuss a long-range glycosyl transfer that occurs during CID for benzylamine-and 9-AmFL-labeled oligosaccharides. The transfer of a fucose across three monosaccharide units was observed only in protonated molecules. To t...

Spider attachment disc silk fibers are spun into a viscous liquid that rapidly solidifies, gluing dragline silk fibers to substrates for locomotion or web construction. Here we report the identification and artificial spinning of a novel attachment disc glue silk fibroin, Pyriform Spidroin 2 (PySp2), from the golden orb weaver Nephila clavipes . MS studies support PySp2 is a constituent of the pyriform gland that is spun into attachment discs. Analysis of the PySp2 protein architecture reveals sequence divergence relative to the other silk family members, including the cob weaver glue silk fibroin PySp1. PySp2 contains internal block repeats that consist of two subrepeat units: one dominated by Ser, Gln, and Ala and the other Pro-rich. Artificial spinning of recombinant PySp2 truncations shows that the Ser-Gln-Ala-rich subrepeat is sufficient for the assembly of polymeric subunits and subsequent fiber formation. These studies support that both orb- and cob-weaving spiders have evolved highly polar block-repeat sequences with the ability to self-assemble into fibers, suggesting a strategy to allow fiber fabrication in the liquid environment of the attachment discs.

Electroenzymatic synthesis often suffers from electrochemical reaction steps which proceed slower than the coupled enzyme reaction. For indirect electrochemical cofactor regeneration, we here report two new mediators with superior properties compared to the established rhodium complex (2,2'-bipyridyl)(pentamethylcyclopentadienyl)rhodium [Cp*Rh(2,2'-bipyridine)]. After constructing a robotic system for fast and reliable cyclic voltammetry measurements, we screened twelve rhodium complexes with substituted 2,2'-bipyridine ligands for their reduction potentials and catalytic activity towards the reduction of NADP. Promising complexes were investigated in more detail by cyclic voltammetry and under batch electrolysis conditions. The new complexes Cp*Rh(5,5'-methyl-2,2'-bipyridine) and Cp*Rh(4,4'-methoxy-2,2'-bipyridine) reduced NADP to NADPH three times faster than the established mediator, resulting in volumetric productivities of up to 136 mmol L À1 d À1 and turnover frequencies of up to 113 h À1. This increased reaction rate of these new mediators makes indirect electrochemical approach significantly more competitive to other methods of cofactor regeneration.Abbreviations: ADH = alcohol dehydrogenase; Ag j AgCl = silver j silver chloride reference electrode; bpy = 2,2'-bipyridine; ci = current increase; Cp* = pentamethylcyclopentadienyl; CV = cyclic voltammetry; Ep = peak potential; equiv = equivalent; NADP/ NADPH = nicotinamide adenine dinucleotide phosphate oxidised/reduced form.