Cooperative Formation of Icosahedral Proline Clusters from Dimers.

ABSTRACT: Ion mobility spectrometry-mass spectrometry and Fourier transform infrared spectroscopy (FTIR) techniques were combined with quantum chemical calculations to examine the origin of icosahedral clusters of the amino acid proline. When enantiopure proline solutions are electrosprayed (using nanospray) from 100 mM ammonium acetate, only three peaks are observed in the mass spectrum across a concentration range of five orders of magnitude: a monomer [Pro+H]⁺ species, favored from 0.001 to 0.01 mM proline concentrations; a dimer [2Pro+H]⁺ species, the most abundant species for proline concentrations above 0.01 mM; and, the dimer and dodecamer [12Pro+2H]²⁺ for 1.0 mM and more concentrated proline solutions. Electrospraying racemic D/L-proline solutions from 100 mM

SUBMITTER: Jacobs AD 

PROVIDER: S-EPMC6884317 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature