Unusual crystal structure of<i>N</i>-substituted maleamic acid – very strong effect of intramolecular hydrogen bonds

Francis, Raju; Raghavaiah, Pallepogu; Pius, Kuruvilla

doi:10.1107/s2052520614018952

Cited by 2 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Usually this is indication of strong intermolecular interactions within the system resulting in aggregation . In fact, derivatives of maleamic acid were found to form hydrogen bonds . At the pure water subphase amide and carbonyl groups were involved in the intermolecular interactions, whereas the lateral carboxylic group was deprotonated and anchored in the water subphase.…”

Section: Resultsmentioning

confidence: 99%

“…44 In fact, derivatives of maleamic acid were found to form hydrogen bonds. 56 At the pure water subphase amide and carbonyl groups were involved in the intermolecular interactions, whereas the lateral carboxylic group was deprotonated and anchored in the water subphase. The more molecules were applied onto the air/water interface, the isotherms were more shifted toward smaller values of area per molecule and below minimal value expected for monolayer.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Langmuir and Langmuir–Blodgett Films of Unsymmetrical and Fully Condensed Polyhedral Oligomeric Silsesquioxanes (POSS)

et al. 2015

View full text Add to dashboard Cite

The search for novel building blocks for preparation of nanostructures of unique properties is crucial for development of functional nanomaterials. Polyhedral oligomeric silsesquioxanes (POSS) may be regarded as organic–inorganic nanoparticles of unusual characteristics, i.e., monodisperse size, high temperature resistance, and small dielectric constant. Here, we study four derivatives of fully condensed polyhedral oligomeric octasilsesquioxanes. Seven corners of the POSS cages are substituted with isobutyl groups forming a hydrophobic tail, whereas the eighth substituent acts as a hydrophilic head due to a judiciously chosen functional group. Such design assures amphiphilic character of POSS molecules with well-defined hydrophilic head and hydrophobic tail. The combination of amphiphilicity, well-defined size and composition, and rheological properties of monolayers makes studied POSS interesting model for self-assembly, thin films, and interfacial investigations. The Langmuir–Blodgett technique is used as a method that provides the best control over the parameters of thin films formation. The functional hydrophilic group strongly influences the behavior of POSS at the air/water interface. The mercapto derivative, which seems most promising for preparation of complex nanostructures, appears to form aggregates and multilayer films. Three other studied derivatives (bearing glycerol unit, maleamic acid, and amino group) behave as classical amphiphiles at the air/water interface.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Langmuir and Langmuir–Blodgett Films of Unsymmetrical and Fully Condensed Polyhedral Oligomeric Silsesquioxanes (POSS)

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In Tables , we listed all published α‐amino acid derivatives and (either linear or, more rarely, cyclic) peptides to the decamer level where single or consecutive fully‐extended (C 5 ) structures were identified by X‐ray diffraction in the last 5/6 years. A few, still unpublished 3D‐structures, characterized by the C 5 form and solved in the Padova laboratory, are presented in Table…”

Section: Detailed Literature Survey On Peptides Since 2012mentioning

confidence: 99%

The fully‐extended conformation in peptides and proteins

et al. 2018

View full text Add to dashboard Cite

The intramolecularly H‐bonded, fully‐extended conformation (C5) of an α‐amino acid residue (and the resulting 2.05‐helix obtained via its propagation) is one of the least extensively investigated types of peptide and protein backbone secondary structure. This situation does still currently occur despite its unique ability to enjoy by far the largest separation per residue among peptide conformations. In this article, we offer a detailed update of our present knowledge on this intriguing 3D‐structure of peptides in the crystal state as obtained from recently published investigations, complemented by a statistical analysis for its occurrence in the crystal structures of α‐amino acid derivatives and peptides available in the Cambridge Structural Database. We have expanded this useful information to the results of a bioinformatics analysis performed on this (so far largely unappreciated) conformation authenticated in all proteins solved by X‐ray diffraction to a resolution of ≤ 1.5 Å. In the last section, we describe the results of our DFT calculations on the conformational preferences of a set of homopeptides (from monomer to octamer) based on as many as six proteins and two noncoded, carefully selected, α‐amino acids. From this literature survey integrated by new energy calculations, we have definitely provided strong support to the thesis that this polypeptide 3D‐structure does indeed exist, it should be not neglected in future studies by structural biochemists, and it represents a very attractive, novel backbone for applications for organic, medicinal, and biomaterials chemists.

show abstract

Unusual crystal structure ofN-substituted maleamic acid – very strong effect of intramolecular hydrogen bonds

Cited by 2 publications

References 16 publications

Langmuir and Langmuir–Blodgett Films of Unsymmetrical and Fully Condensed Polyhedral Oligomeric Silsesquioxanes (POSS)

Langmuir and Langmuir–Blodgett Films of Unsymmetrical and Fully Condensed Polyhedral Oligomeric Silsesquioxanes (POSS)

The fully‐extended conformation in peptides and proteins

Contact Info

Product

Resources

About