Characterization of the N-linked glycosylation site of recombinant pectate lyase

Recombinant pectate lyase from Aspergillus niger was overexpressed in Aspergillus nidulans. The two recombinant proteins produced differed in molecular mass by 1200 Da, which suggested that the larger molecular weight protein was glycosylated. The deduced amino acid sequence was searched for potential N-linked glycosylation sites, and one potential site was identified at residue 64. The proteins were analyzed for their ability to bind various lectins as an assay for the presence of carbohydrates. The proteins were then digested with trypsin to facilitate the isolation of the potential glycosylation site. The resulting digestion products were subsequently analyzed by liquid chromatography/mass spectrometry using in-source collision induced dissociation to detect glycopeptides. Once the glycopeptide had been identified, treatment with an endoglycosidase both verified the location of glycosylation and identified the mass of the glycan. The Complex Carbohydrate Structural Database was searched for possible N-linked structures with the same mass, and the suggested primary sequence was confirmed by an exoglycosidase digestion. The data demonstrated that the larger recombinant protein contained a high mannose N-linked structure (Man(5)GlcNAc(2)) attached to N-64, while this site was not occupied in the smaller protein.     

Current-particle matrix elements in ACD

Using anisotropic chromo-dynamics (ACD) we compute the relevant one-particle matrix elements of the electroweak currents. Good agreement with experiments is found for light mesons, while some discrepancies for heavy mesons (?, ?′) are well understood within the limitations of our approximations.     

Structural properties, conformational stability and oxygen binding properties of Penaeus monodon hemocyanin

Hemocyanin sequences allineament shows the presence of highly invariant regions especially in the active site and in the tight intersubunits interaction sites. Comparing the aminoacids in contact regions between monomers is possible to interpret the stability of hexamers.     

An asymptotic formula for the pion decay constant in a large volume

We derive an asymptotic formula à la Lüscher for the finite-volume correction to the pion decay constant: this is expressed as an integral over the 3π|A_μ|0 amplitude after proper subtraction of the pion pole contribution. We analyze the formula numerically at leading and next-to-leading order in the chiral expansion.     

Long distance effects inb→s exclusive decays

We estimate long distance corrections to radiativeB →K ^*γ and to non leptonicB→Kπ,B→K ^*π,B→Kσ,B→K ^*σ,B→KΦ andB→K ^*Φ decays generated by the ( \(\overline b\) c) ( \(\overline c\) s) part of the non leptonic weak Hamiltonian. While vanishing in the vacuum saturation approximation, these corrections are finite if one includes single particle charmed states between the currents in the Hamiltonian. We find small effects in radiative decays, but significant contributions to several non leptonic processes.     

Supersymmetric contributions to direct CP violation in K→ππγ decays

We analyze the supersymmetric contributions to direct–CP–violating observables in K→ππγ decays induced by gluino–mediated magnetic–penguin operators. We find that ε′_+−γ and the differential width asymmetry of K^±→π^±π⁰γ decays could be substantially enhanced with respect to their Standard Model values, especially in the scenario where ε′/ε is dominated by supersymmetric contributions. These observables could therefore provide a useful tool to search for New Physics effects in |ΔS|=1 transitions, complementary to ε′/ε and rare decays.     

The pion mass in finite volume

We determine the relative pion mass shift due to the finite spatial extent L of the box by means of two-flavor chiral perturbation theory and the one-particle Lüscher formula. We use as input the expression for the infinite volume forward scattering amplitude up to next-to-next-to-leading order and can therefore control the convergence of the chiral series. A comparison to the full leading order chiral expression for the pion mass in finite volume allows us to check the size of subleading terms in the large-L expansion.Received: 19 November 2003, Published online: 18 February 2004