Biology subjects

Gisonno, R. A.

Publications and source records attributed to Gisonno, R. A..

3 recordsLinked to original sources

bioRxiv2020

Dataset of the construction and characterization of stable biological nanoparticles

We suggest that the structural flexibility is key for certain proteins in order to fulfill functions that are required to interact with biological membranes, and that intra-chain chemical crosslinking may result in a different arrangement of protein with lipids. As interaction with biological membranes and lipids is a function attributed to many proteins in circulation, we intended to characterize an experimental design that helps in the study of many biological protein structures and their function. But in addition, by introducing intra-chain crosslinking, we obtained discoidal nano platforms that are stable under different conditions of temperate and time incubation. These platforms might be an excellent model to employ as biological carriers of intrinsic or external molecules. Thus, data shown here clearly strengthen the usefulness of an easy, accessible and inexpensive tool not only to study protein-lipid interactions, but to be used in different biological fields that require the transport of organic compounds.

biophysics↗

bioRxiv2020

Understanding the role of apolipoprotein A-I in atherosclerosis. Post-translational modifications synergize dysfunction?

BackgroundThe identification of dysfunctional human apolipoprotein A-I (apoA-I) in atherosclerotic plaques suggests that protein structure and function may be hampered under a chronic pro inflammatory scenario. Moreover, the fact that natural mutants of this protein elicit severe cardiovascular diseases (CVD) strongly indicates that the native folding could shift due to the mutation, yielding a structure more prone to misfold or misfunction. To understand the events that determine the failure of apoA-I structural flexibility to fulfill its protective role, we took advantage of the study of a natural variant with a deletion of the residue lysine 107 (K107del) associated with atherosclerosis. MethodsBiophysical approaches, such as electrophoresis, fluorescence and spectroscopy were used to characterize proteins structure and function, either in the native conformation or under oxidation or intramolecular crosslinking. ResultsK107del structure was more flexible than the protein with the native sequence (Wt) but interactions with artificial membranes were preserved. Instead, structural restrictions by intramolecular crosslinking impaired the Wt and K107del lipid solubilization function. In addition, controlled oxidation decreased the yield of the native dimer conformation for both variants. ConclusionsWe conclude that even though mutations may alter protein structure and spatial arrangement, the highly flexible conformation compensates the mild shift from the native folding. Instead, post translational apoA-I modifications (probably chronic and progressive) are required to raise a protein conformation with significant loss of function and increased aggregation tendency. General SignificanceThe results learnt from this variant strength a close association between amyloidosis and atherosclerosis. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/142844v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@265244org.highwire.dtl.DTLVardef@1e30814org.highwire.dtl.DTLVardef@279375org.highwire.dtl.DTLVardef@421fd9_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights-Oxidation is clue to induce protein misfolding -Natural mutation does not seem critical as a sole reason to determine pathogenicity -Atherosclerosis and amyloidosis are closely related -Intramolecular crosslinking restrains protein flexibility and function

biophysics↗

bioRxiv2019

N-terminal mutants of human apolipoprotein A-I: structural perturbations associated to protein misfolding

Since the early description of different human apolipoprotein A-I variants associated to amyloidosis, the reason that determines its deposition inducing organ failure has been under research. To shed light into the events associated to protein aggregation, we studied the effect of the structural perturbations induced by the replacement of a Leucine in position 60 by an Arginine as it occurs in the natural amyloidogenic variant (L60R). Circular dichroism, intrinsic fluorescence measurements and assays of binding to ligands indicate that L60R is more unstable, more sensitive to proteolysis and interacts with sodium dodecyl sulfate (a model of negative lipids) more than the protein with the native sequence and other natural variant tested, involving a replacement of a Trytophan by and Arginine in the amino acid 50 (W50R). In addition, the small structural rearrangement observed under physiological pH leads to the release of tumor necrosis factor and interleukin-l{beta} from a model of macrophages. Our results strongly suggest that the chronic disease may be a consequence of the loss in the native conformation which alters the equilibrium among native and cytotoxic proteins conformation.

biophysics↗