2,624 research outputs found
Exploitation of proteomics strategies in protein structure-function studies
Mass spectrometry plays a central role in structural proteomics, particularly in highly intensive structural genomics projects. This review paper reports some examples taken from recent work from the authors' laboratory and is aimed at showing that modem proteomics strategies are instrumental in the integration of structural genomic projects in fields such as: (i) protein-protein interactions, (ii) protein-DNA interactions, (iii) protein-ligand interactions, and (iv) protein-folding intermediates
On a Dirichlet problem with -Laplacian and parametric concave-convex nonlinearity
A homogeneous Dirichlet problem with -Laplace differential operator
and reaction given by a parametric -convex term plus a -concave one is
investigated. A bifurcation-type result, describing changes in the set of
positive solutions as the parameter varies, is proven. Since for
every admissible the problem has a smallest positive solution , both monotonicity and continuity of the map are studied.Comment: 12 pages, comments are welcom
Moser iteration applied to elliptic equations with critical growth on the boundary
This paper deals with boundedness results for weak solutions of an elliptic
equation where the functions are Carath\'eodory functions satisfying certain
-structure conditions that have critical growth even on the boundary. Based
on a modified version of the Moser iteration we are able to prove that every
weak solution of our problem is bounded up to the boundary. Under some
additional assumptions this leads directly to -regularity for
weak solutions of the problem.Comment: 17 pages; comments are welcom
Deamidation at Asparagine and Glutamine As a Major Modification upon Deterioration/Aging of Proteinaceous Binders in MuralPaintings
Proteomic strategies are herein proved to be a
complementary approach to the well established amino acid
composition analysis for the characterization of the aging and
deterioration phenomena occurring to proteinaceous materials
in works-of-art. Amino acid analyses on several samples demonstrated
that proteins in the frescoes from the Camposanto
Monumentale in Pisa are deteriorated as revealed by the
decrease in Met, Lys, and Tyr content and by the presence in
all the samples of amino malonic acid as a result of Ser, Phe, and
Cys oxidation. Proteomic analysis identified deamidation at Asn
and Gln as a further major event occurred. This work paves the
way to the exploitation of proteomic strategies for the investigation
of the molecular effects of aging and deterioration in
historical objects. Results show that proteomic searches for
deamidation by liquid chromatography-tandem mass spectrometry
(LC-MS/MS) could constitute a routine analysis for paintings or any artistic and historic objects where proteins are present.
Peptides that can be used as molecular markers when casein is present were identified
Structural characterization of the M* partly folded intermediate of wild-type and P138A EcAspAT
A combination of spectroscopic techniques, hydrogen/deuterium exchange, and limited proteolysis experiments coupled to mass spectrometry analysis was used to depict the topology of the monomeric M*partly folded intermediate of aspartate aminotransferase from Escherichia coli in wild type (WT) as well as in a mutant form in which the highly conserved cis-proline at position 138 was replaced by a trans-alanine (P138A). Fluorescence analysis indicates that, although M* is an off-pathway intermediate in the folding of WT aspartate aminotransferase from E. coli, it seems to coincide with an on-pathway folding intermediate for the P138A mutant. Spectroscopic data, hydrogen/deuterium exchange, and limited proteolysis experiments demonstrated the occurrence of conformational differences between the two M*intermediates, with P138A-M* being conceivably more compact than WT-M*. Limited proteolysis data suggested that these conformational differences might be related to a different relative orientation of the small and large domains of the protein induced by the presence of the cis-proline residue at position 138. These differences between the two M* species indicated that in WT-M* Pro138 is in the cis conformation at this stage of the folding process. Moreover, hydrogen/deuterium exchange results showed the occurrence of few differences in the native N2 forms of WT and P138A, the spectroscopic features and crystallographic structures of which are almost superimposabl
New supersymmetric Wilson loops in ABJ(M) theories
We present two new families of Wilson loop operators in N= 6 supersymmetric
Chern-Simons theory. The first one is defined for an arbitrary contour on the
three dimensional space and it resembles the Zarembo's construction in N=4 SYM.
The second one involves arbitrary curves on the two dimensional sphere. In both
cases one can add certain scalar and fermionic couplings to the Wilson loop so
it preserves at least two supercharges. Some previously known loops, notably
the 1/2 BPS circle, belong to this class, but we point out more special cases
which were not known before. They could provide further tests of the
gauge/gravity correspondence in the ABJ(M) case and interesting observables,
exactly computable by localizationComment: 9 pages, no figure. arXiv admin note: text overlap with
arXiv:0912.3006 by other author
Least energy sign-changing solution for degenerate Kirchhoff double phase problems
In this paper we study the following nonlocal Dirichlet equation of double
phase type
\begin{align*}
-\psi \left [ \int_\Omega \left ( \frac{|\nabla u |^p}{p} + \mu(x)
\frac{|\nabla u|^q}{q}\right)\,\mathrm{d} x\right] \mathcal{G}(u) = f(x,u)\quad
\text{in } \Omega, \quad u = 0\quad \text{on } \partial\Omega,
\end{align*}
where is the double phase operator given by
\begin{align*}
\mathcal{G}(u)=\operatorname{div} \left(|\nabla u|^{p-2}\nabla u + \mu(x)
|\nabla u|^{q-2}\nabla u \right)\quad u\in W^{1,\mathcal{H}}_0(\Omega),
\end{align*}
, , is a bounded domain with Lipschitz
boundary , , , , for
, with , and , and
is a Carath\'{e}odory function
that grows superlinearly and subcritically. We prove the existence of two
constant sign solutions (one is positive, the other one negative) and of a
sign-changing solution which has exactly two nodal domains and which turns out
to be a least energy sign-changing solution of the problem above. Our proofs
are based on variational tools in combination with the quantitative deformation
lemma and the Poincar\'{e}-Miranda existence theorem
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