n→π* interactions in poly(lactic acid) suggest a role in protein folding

Newberry, Robert W.; Raines, Ronald T.

doi:10.1039/c3cc44317e

Cited by 61 publications

(55 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consider poly(lactic acid) (PLA), a biodegradable polyester (Figure 8A). 26 Fiber diffraction has shown that the backbone dihedral angles in PLA resemble those of the PPII helix of peptides, which takes advantage of numerous n →π* interactions (vide supra). Computation placed the average energy of an n →π* interaction in PLA at 0.44 kcal/mol, and analysis of small-molecule crystal structures demonstrated characteristic pyramidalization of the acceptor carbonyl group that results from accepting an n →π* interaction.…”

Section: Contributions To Other Polymersmentioning

confidence: 99%

The n→π* Interaction

2017

Self Cite

View full text Add to dashboard Cite

ConspectusThe carbonyl group holds a prominent position in chemistry and biology not only because it allows diverse transformations but also because it supports key intermolecular interactions, including hydrogen bonding. More recently, carbonyl groups have been found to interact with a variety of nucleophiles, including other carbonyl groups, in what we have termed an n→π* interaction. In an n→π* interaction, a nucleophile donates lone-pair (n) electron density into the empty π* orbital of a nearby carbonyl group. Mixing of these orbitals releases energy, resulting in an attractive interaction. Hints of such interactions were evident in small-molecule crystal structures as early as the 1970s, but not until 2001 was the role of such interactions articulated clearly.These non-covalent interactions were first discovered during investigations into the thermostability of the proline-rich protein collagen, which achieves a robust structure despite a relatively low potential for hydrogen bonding. It was found that by modulating the distance between two carbonyl groups in the peptide backbone, one could alter the conformational preferences of a peptide bond to proline. Specifically, only the trans conformation of a peptide bond to proline allows for an attractive interaction with an adjacent carbonyl group, so when one increases the proximity of the two carbonyl groups, one enhances their interaction and promotes the trans conformation of the peptide bond, which increases the thermostability of collagen.More recently, attention has been paid to the nature of these interactions. Some have argued that rather than resulting from electron donation, carbonyl interactions are a particular example of dipolar interactions that are well-approximated by classical mechanics. However, experimental evidence has demonstrated otherwise. Numerous examples now exist where an increase in the dipole moment of a carbonyl group decreases the strength of its interactions with other carbonyl groups, demonstrating unequivocally that a dipolar mechanism is insufficient to describe these interactions. Rather, these interactions have important quantum-mechanical character that can be evaluated through careful experimental analysis and judicious use of computation.Although individual n→π* interactions are relatively weak (∼0.3–0.7 kcal/mol), the ubiquity of carbonyl groups across chemistry and biology gives the n→π* interaction broad impact. In particular, the n→π* interaction is likely to play an important role in dictating protein structure. Indeed, bioinformatics analysis suggests that approximately one-third of residues in folded proteins satisfy the geometric requirements to engage in an n→π* interaction, which is likely to be of particular importance for the α-helix. Other carbonyl-dense polymeric materials like polyesters and peptoids are also influenced by n→π* interactions, as are a variety of small molecules, some with particular medicinal importance. Research will continue to identify molecules whose conformation and activity are affect...

show abstract

Section: Contributions To Other Polymersmentioning

confidence: 99%

The n→π* Interaction

2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…[38][39][40] Their further role in protein structure, folding and stability can be well anticipated. 37,[41][42][43] There are numerous reports on hydrogen bonded carbonyl complexes by theoreticians and experimentalists [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] in the past and even today. [62][63][64][65][66][67][68] For example, the earlier work by Bobadova-Parvanova and his co-worker investigated the hydrogen bonded complexes between open-chain substituted aliphatic carbonyl compounds and hydrogen fluoride at the HF/6-31G * * level.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Characterization of Hydrogen Bonding Interactions between RCHO (R = H, CN, CF3, OCH3, NH2) and HOR′(R′ = H, Cl, CH3, NH2, C(O)H, C6H5)

Kaur

2015

J Chem Sci

View full text Add to dashboard Cite

In this work, density functional theory and ab initio molecular orbital calculations were used to investigate the hydrogen bonded complexes of type RCHO· · · HOR (R = H, CN, CF 3 , OCH 3 , NH 2 ; R = H, Cl, CH 3 , NH 2 , C(O)H, C 6 H 5 ) employing 6-31++g** and cc-pVTZ basis sets. Thus, the present work considers how the substituents at both the hydrogen bond donor and acceptor affect the hydrogen bond strength. From the analysis, it is reflected that presence of -OCH 3 and -NH 2 substituents at RCHO greatly strengthen the stabilization energies, while -CN and -CF 3 decrease the same with respect to HCHO as hydrogen bond acceptor. The highest stabilization results in case of (H 2 N)CHO as hydrogen bond acceptor. The variation of the substituents at -OH functional group also influences the strength of hydrogen bond; nearly all the substituents increase the stabilization energy relative to HOH. The analysis of geometrical parameters; proton affinities, charge transfer, electron delocalization studies have been carried out.

show abstract

“…Simulations studies conducted on some synthetic polymers (e.g. m-terphenyl-based π-conjugated polymer [6], poly(ethylene glycol) (PEG) [7], poly(ethylene imine) (PEI) [8], squaraine polymers [9]) shown their tendency to form helixes.…”

Section: Introductionmentioning

confidence: 99%

Helical structure of linear homopolymers

Bolboacă

Jäntschi

2018

Powder Metallurgy and Advanced Materials

View full text Add to dashboard Cite

The aim of our research was to conduct a computational study on helical geometries of several homopolymers. Simple helix of polymers with seventeen (poly(lactic acid)) or eighteen (poly(1-chloro-trans-1-butenylene), poly(1-methyl-trans-1-butenylene), poly(1,4,4-trifluoro-trans-1-butenylene), polyacrylonitrile and respectively polychlorotrifluoroethylene) monomers were investigated. The X, Y, and Z coordinates obtained after optimization of the geometry of polymers were used as input data to identify the rotation and translation of the coordinates and respectively the coefficient of the helix. The values of interest were calculated by minimization of residuals using two different protocols. The first protocol investigated the whole polymer by imposing (step 1) or not (step 2) a fixed value of the helix coefficient. The second protocol investigated by minimization of residuals if the monomer (one or two) from each end of the polymer is or not an outlier of the helical geometry of the polymer.

show abstract

n→π* interactions in poly(lactic acid) suggest a role in protein folding

Cited by 61 publications

References 39 publications

The n→π* Interaction

The n→π* Interaction

Theoretical Characterization of Hydrogen Bonding Interactions between RCHO (R = H, CN, CF3, OCH3, NH2) and HOR′(R′ = H, Cl, CH3, NH2, C(O)H, C6H5)

Helical structure of linear homopolymers

Contact Info

Product

Resources

About