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The structural and dynamic aspects of the aggregation as observed in state-of-the-art computer simulations of amyloid-forming peptides are studied with an emphasis on the activation-relaxation technique (ART). It is concluded that numerical methods, including ART- optimized potential for efficient peptide-structure prediction (OPEP) is playing a central role in proposing structural and dynamic information.

The properties of bile acid transport and gene expression in the canaliculus of sister of P-glycoprotein [Spgp](super -/-) mice are characterized and the hypothesis that Mdr1 could function as an alternative transporter for cholic acid is tested. It is shown that plasma membrane vesicles isolated from a drug resistant cell line expressing high levels of P-glycoprotein are capable of transporting bile acids, albeit with a 5-fold lower affinity compared to Spgp.

Negative cooperativity in the isothermal titration microcalorimetry (ITC) binding data of asialofeutin (ASF), a glycoprotein that possesses nine LacNAc epitopes, to galectin-1, -2, -3, -4, -5, and -7 and truncated, monomer version of galectin-3 and -5 which are members of a family of animal lectins is demonstrated. The results indicate that the galactins bind with fractional, high affinities to multivalent glycoproteins such as ASF, independent of the quaternary structures of the galectins.

Conformational changes in gp120-gp41 expressed on cells as a function of time following interactions of Env-expressing cells with target cells using a nonspecific probe is monitored using analytical and quantitative video microscopy. The reactivity of triggered gp41 to the NC-1 monoclonal antibody, which is demonstrated to bind to N-helical gp41, increased rapidly to a maximal level in the primed state but decreased once stable fusion junctions had formed.

The mechanism by which alpha1-acid glycoprotein (AGP), as well as its recombinant fragment AGP(sub 118-201, interacts exclusively with the active form of plasminogen activator inhibitor 1 (PAI-1) and stabilizes its conformation is described. Results suggest that AGP binding stabilizes the active conformation of PAI-1 by restricting the movement of beta-sheet A and thereby preventing insertion of the reactive center loop.

The use of synthetic oligosaccharide oxazolines, as donor substrates for glycopeptide synthesis is reported. The use of synthetic oligosaccharide oxazolines as the donor substrates for the endo-beta-N-acetylglucosaminidase (ENGase)-catalyzed transglycosylation not only expanded the substrate availability but also resulted a substantial enhancement of the synthetic efficiency, allowing a high-yield synthesis of large N-glycopeptides.

A model cosolvent, ethanol, has profound and diversified effects on the amyloidogenic self-assembly of insulin, yielding spectroscopically and morphologically distinguishable forms of beta-aggregates. The alcohol reduces hydrodynamic radii of insulin molecules, decreases enthalpic costs associated with aggregation-prone intermediate states, and accelerates the aggregation itself.

A protocol was introduced using ammonium carbamate in methanol to the amination of crude chitobiose leading to 1, beta-aminochitobiose. The new amination protocol leads to an improved synthesis of the key chitobiosyl-asparagine building block for the solid-phase peptide synthesis (SPPS).

The three known GCN4 coiled-coil mutants that oligomerize in solution into dimers, trimers, or tetramers, together with the 70-mer wild-type peptide (N70) are investigated. The results gathered from the investigation suggest that the local assembly of fusion peptides, facilitated by coiled-coil bloomers, increases lipid-mixing ability.

The ability of a destabilized test protein, monomer-B to consistently form amyloid fibrils is reported. It is demonstrated that a designed protein interface can effectively block protein fibril formation.

The structural properties and ligand-binding capacity of acid glycoprotein under mild acidic conditions and its interactions with liposomes prepared from neutral or aionic lipids and the neutral drug, progesterone is investigated. The results indicate that AGP has a unique structure on the membrane-aided surface under mild acidic conditions.

Natural glycopeptides and glycoproteins exhibit a large structural diversity, which can be mimicked by synthetic glycopeptides derivatives to assist investigation of biological functions and structure activity relationship. The Staudinger reaction could be optimized for the synthesis of dendronized glycopeptide mimetics resembling valuable oligofunctional building blocks of an A(sub 3)B- and A(sub 3)BC-type.

The interaction of calreticulin (CRT) with various sugar moieties of glycoproteins is investigated. The residues implicated by the CRT-Glc1Man3 complex model are systematically mutated to categorize the role played by each of the subsites of calreticulin toward the glycan binding.

The known retention of relative stereo chemistry inherent in the [3+2]dipolar cycloaddition reactions of nitrile oxides were used to prepare both the trans and cis isomers of a ring-hydroxylated metabolite of the GPIIb/IIIa antagonist XV459,the active drug form of Roxifiban. The comparisons between the synthetic standards with the isolated metabolite show the trans relative stereochemistry in this material.

The preformed amyloid fibrils of hen lysozyme are found to form nematic liquid crystal phases. The physicochemical properties of proteins and their aggregates, such as their ability to form liquid crystal phases, have provided new opportunities for the development of functional, biological materials that self-structure on a nanoscale level.

A study was conducted to show that it is possible to acquire and analyze X-ray scattering patterns from aligned amyloid fibrils in solution under conditions that are similar to those used for characterization by other biophysical and spectroscopic techniques. The examination of amyloid fibrils show that the cross-[beta] structure is present in individual fibrils and is unaffected by the level of sample hydration suggesting that individual hydrated fibrils contain a stack of two or more sheets whose interfaces are inaccessible to bulk water.

A study demonstrates that it is possible to successfully display a porphyrin binding protein on an amyloid fibril scaffold and incorporate heme to form a functional b-type cytochrome. The reproductibility and stoichiometric character of the system suggests that further investigations could provide important insights into the nature of the amyloid structure and assembly process.

The N-acetylgalactosamine alpha-O-threonine can be genetically encoded in Escherichia coli using an evolved Methanococcus jannaschii Tyr-tRNA synthetase (MjTyrRS) pair. A general approach is developed to co-translationally incorporate glycosyl amino acids into proteins in vivo that provide an expedient route to prepare homogeneous glycoproteins.

A semisynthetic approach to glycosylated EPO is targeted toward investigations of the potential to ligate the synthetic glycopeptide thioesters to the bacterially derived fragments. Use of the detergents N-laurylsarcosine and Triton X-100 to aid solubility were investigated along with it.

The constraints on supramolecular structure that can be obtained from two-dimensional solid-state nuclear magnetic resonance (NMR) spectra of amyloid fibrils with uniform isotopic labeling of multiple residues is demonstrated. The two-dimensional spectra also provide information about the degree of supramolecular structural order in amyloid fibrils.

The retraction of two papers from the lab of prominent US chemist Peter Schultz is a setback for researchers trying to synthesize and study glycoproteins--proteins with sugar chains attached. The [...]