Influence of cation-pi interactions to the structural stability of prokaryotic and eukaryotic translation elongation factors

Graphene oxide and its derivatives films for sustained-release trace element zinc based on cation-π interaction

Preventing and controlling agricultural non-point-source pollution, advancing the agricultural industry, and facilitating cation-π interaction to address cation instability and fertilizer loss are crucial for advancing agricultural sustainability. Due to the unique π-bond characteristics of GO (graphene oxide), it was selected as a cation carrier to improve fertilizer anti-loss capabilities and facilitate the effective release of nutrient ions. By adjusting the interface properties of GO, RGO (rippled graphene oxide) and CGO (crumpled graphene oxide) were successfully prepared, and their interactions with cations and the impact on sustained-release performance were studied. The selected optimal kinetic model provides a theoretical basis for material design. The results indicate that RGO-Zn1 (Zn2+/RGO = 16.7%) can not only effectively control agricultural non-point source pollution but also promote the cultivation of high-zinc rice. This study not only proposes an innovative solution for soil improvement and agricultural transformation and upgrading but also offers fundamental scientific insights into the cation-π interaction mechanism during transmembrane permeation.

Molecular modeling of the human hemoglobin-haptoglobin complex sheds light on the protective mechanisms of haptoglobin

Hemoglobin (Hb) plays a critical role in human physiological function by transporting O2. Hb is safe and inert within the confinement of the red blood cell but becomes reactive and toxic upon hemolysis. Haptoglobin (Hp) is an acute-phase serum protein that scavenges Hb and the resulting Hb-Hp complex is subjected to CD163-mediated endocytosis by macrophages. The interaction between Hb and Hp is extraordinarily strong and largely irreversible. As the structural details of the human Hb-Hp complex are not yet available, this study reports for the first time on insights of the binding modalities and molecular details of the human Hb-Hp interaction by means of protein-protein docking. Furthermore, residues that are pertinent for complex formation were identified by computational alanine scanning mutagenesis. Results revealed that the surface of the binding interface of Hb-Hp is not flat and protrudes into each binding partner. It was also observed that the secondary structures at the Hb-Hp interface are oriented as coils and α-helices. When dissecting the interface in more detail, it is obvious that several tyrosine residues of Hb, particularly β145Tyr, α42Tyr and α140Tyr, are buried in the complex and protected from further oxidative reactions. Such finding opens up new avenues for the design of Hp mimics which may be used as alternative clinical Hb scavengers.

Investigation of cation-π interactions in sugar-binding proteins

Cation-π interaction is a non-covalent binding force that plays a significant role in protein stability and drug-receptor interactions. In this work, we have investigated the structural role of cation-π interactions in sugar-binding proteins (SBPs). We observed 212 cation-π interactions in 53 proteins out of 59 SBPs in dataset. There is an average one energetically significant cation-π interaction for every 66 residues in SBPs. In addition, Arg is highly preferred to form cation-π interactions, and the average energy of Arg-Trp is high among six pairs. Long-range interactions are predominant in the analyzed cation-π interactions. Comparatively, all interaction pairs favor to accommodate in strand conformations. The analysis of solvent accessible area indicates that most of the aromatic residues are found on buried or partially buried whereas cationic residues were found mostly on the exposed regions of protein. The cation-π interactions forming residues were found that around 43% of cation-π residues had highly conserved with the conservation score ≥6. Almost cationic and π-residues equally share in the stabilization center. Sugar-binding site analysis in available complexes showed that the frequency of Trp and Arg is high, suggesting the potential role of these two residues in the interactions between proteins and sugar molecules. Our observations in this study could help to further understand the structural stability of SBPs.