The effect of N-methylation on the conformational landscape of alanine: the case of N-methyl-l-alanine. Issue 46 (14th November 2018)

• Record Type: Journal Article
• Authors: Neeman, E. M.; León, I.; Alonso, E. R.; Kolesniková, L.; Mata, S.; Alonso, J. L.
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 46(2018)
• Page Start: 29159
• Page End: 29165
• Publication Date: 2018-11-14
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp06043f
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The non-proteinogenic amino acid N -methyl-l -alanine has been brought into the gas phase using laser ablation techniques and studied by high resolution chirped pulse and molecular-beam Fourier transform microwave spectrometers coupled to supersonic expansion. Abstract : The non-proteinogenic amino acid N -methyl-l -alanine has been brought into the gas phase using laser ablation techniques and studied by high resolution chirped pulse and molecular-beam Fourier transform microwave spectroscopies coupled to supersonic expansion. Four conformers showing the three types of hydrogen bond interactions I (NH⋯OC), II (OH⋯N) and III (N–H⋯O–H) have been unambiguously identified, based on the comparison of the experimental rotational and 14 N nuclear quadrupole constants with the calculated ab initio values. The observation of a type III conformer evidences the role of methyl groups in both sides to impose the steric hindrance, precluding the relaxation from type III to type I conformers and explains the responsibility for the unique conformational landscape observed in the case of NMA.