Influence of cation-π interactions to the structural stability of phycocyanin proteins: A computational study.

The influences of cation-π interactions in phycocyanin proteins and their environmental preferences were analyzed. The number of interactions formed by arginine showed to be higher than those formed by the lysine in the cationic group, while histidine is comparatively higher than phenylalanine and N-terminal residue in the π group. Arg-Tyr and Arg-Phe interacting pairs are predominant among the various pairs analyzed.

Antipsychotic clozapine binding to alpha-2-macroglobulin protects interacting partners against oxidation and preserves the anti-proteinase activity of the protein.

In this study, the interaction between clozapine, an atypical antipsychotic drug, and alpha-2-macroglobulin (αM), a multipurpose anti-proteinase, was investigated under simulated (patho) physiological conditions using multiple spectroscopic techniques and molecular modeling. It was found that αM binds clozapine with a moderate affinity (the binding constant of 0.9 × 10 M at 37 °C).

Nutraceutical phycocyanobilin binding to catalase protects the pigment from oxidation without affecting catalytic activity.

Phycocyanobilin is a dark blue linear tetrapyrrole chromophore covalently attached to protein subunits of phycobiliproteins present in the light-harvesting complexes of the cyanobacteria Arthrospira platensis (Spirulina "superfood"). It shows exceptional health-promoting properties and emerging use in various fields of bioscience and industry. This study aims to examine the mutual impact of phycocyanobilin interactions with catalase, a life-essential antioxidant enzyme.

Computational Analysis of Non-covalent Interactions in Phycocyanin Subunit Interfaces.

Protein-protein interactions are an important phenomenon in biological processes and functions. We used the manually curated non-redundant dataset of 118 phycocyanin interfaces to gain additional insight into this phenomenon using a robust inter-atomic non-covalent interaction analyzing tool PPCheck. Our observations indicate that there is a relatively high composition of hydrophobic residues at the interfaces.

Opposite clozapine and ziprasidone effects on the reactivity of plasma albumin SH-group are the consequence of their different binding properties dependent on protein fatty acids content.

Antipsychotic drugs interfere with the antioxidant defense system provoking complex and often toxicological effects. Here we examined differences in plasma albumin reduced free thiol (SH) group content and its reactivity as a consequence of clozapine (CLZ) and ziprasidone (ZIP) binding. Chronic administration of CLZ reduced, whereas treatment with ZIP increased albumin-SH content in rats.

Digestion by pepsin releases biologically active chromopeptides from C-phycocyanin, a blue-colored biliprotein of microalga Spirulina.

C-phycocyanin, the major protein of cyanobacteria Spirulina, possesses significant antioxidant, anti-cancer, anti-inflammatory and immunomodulatory effects, ascribed to covalently attached linear tetrapyrrole chromophore phycocyanobilin. There are no literature data about structure and biological activities of released peptides with bound chromophore in C-phycocyanin digest. This study aims to identify chromopeptides obtained after pepsin digestion of C-phycocyanin and to examine their bioactivities.

Contribution of anion-π interactions to the stability of Sm/LSm proteins.

We have analyzed the influence of anion-π interactions to the stability of Sm/LSm assemblies. The side chain of Glu is more likely to be in anion-π interactions than Asp. Phe has the highest occurrence in these interactions than the other two π residues.

Contribution of cation-π interactions to the stability of Sm/LSm oligomeric assemblies.

In this work, we have analyzed the influence of cation-π interactions to the stability of Sm/LSm assemblies and their environmental preferences. The number of interactions formed by arginine is higher than lysine in the cationic group, while histidine is comparatively higher than phenylalanine and tyrosine in the π group. Arg-Tyr interactions are predominant among the various pairs analyzed.