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

Abstract

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. The furcation level of multiple cation-π interactions is much higher than that of single cation-π interactions in Sm/LSm interfaces. We have found hot spot residues forming cation-π interactions, and hot spot composition is similar for all aromatic residues. The Arg-Phe pair has the strongest interaction energy of -8.81 kcal mol(-1) among all the possible pairs of amino acids. The extent of burial of the residue side-chain correlates with the ΔΔG of binding for residues in the core and also for hot spot residues cation-π bonded across the interface. Secondary structure of the cation-π residues shows that Arg and Lys preferred to be in strand. Among the π residues, His prefers to be in helix, Phe prefers to be in turn, and Tyr prefers to be in strand. Stabilization centers for these proteins showed that all the five residues found in cation-π interactions are important in locating one or more of such centers. More than 50 % of the cation-π interacting residues are highly conserved. It is likely that the cation-π interactions contribute significantly to the overall stability of Sm/LSm proteins.

Janus head type lone pair–π–lone pair and S⋯F⋯S interactions in retaining hexafluorobenzene

“…It is apparent from the recent literature that lone pair-π (lp⋯π) interactions are weak yet important for the stabilization of threedimensional structures of biomolecules 1 in addition to other well-established weak interactions such as hydrogen bonding, anion-π interactions, and cation-π interactions. Some experimental evidence has been reported very recently to establish the applications of anion-π interactions [2][3][4][5][6] and cation-π interactions [7][8][9][10] while the lp⋯π interactions are yet to be proved useful in small molecular systems. To the best of our knowledge, all the reported synthetic molecular systems that exhibit lp⋯π interactions were discovered serendipitously.…”

Investigations on the role of cation-π interactions in active centers of superoxide dismutase

“…9,20 Generally the composition of cation- interaction forming residues is similar to other globular proteins. [39][40][41][42] The organization of multicomponent supramolecular assemblies is often governed by multiple noncovalent interactions. 43 Ternary complexes are the…”

Triazine based eccentric Piedfort units towards a single source hydrogen bonded network

“…It is apparent from the literature that lpÁ Á Áp interactions are weak yet important for the stabilization of three-dimensional structures of biomolecules 23 in addition to other well-established weak interactions such as hydrogen-bonding, anionÁ Á Áp interactions, and cationÁ Á Áp interactions. A lot of experimental evidence has been reported in the literature to establish the applications of anionÁ Á Áp interactions [24][25][26][27][28] and cationÁ Á Áp interactions, [29][30][31][32] while lpÁ Á Áp interactions are yet to be proven useful in small molecular systems. sym-Triaryloxytriazines 5,22 have an interesting structural feature of comprising the peripheral aryl rings almost perpendicular to the central C 3 N 3 ring and form stacked PUs (D CgÁ Á ÁCg = 3-4 Å), which eventually are the synthons for higher level supramolecular assemblies.…”