Measurments of Carotenoid Levels in Human Serum and a Catalog of the Lutein Conformation Populations from Semi-empirical Calculations

Direct Observation of Differences of Carotenoid Polyene Chain cis/trans Isomers Resulting from Structural Topology

“…A pool of candidate structures with varying numbers of cis bond geometries of the polyene chain (including s-cis and s-trans conformations) for the lutein and zeaxanthin molecular and fragment ions were generated and optimized at the B3LYP/G-311G level. 24 Energies of formation were calculated for all the obtained structures after a series of simulated annealing and geometry optimization cycles using AMBER03 force field in YASARA 32 (analogous to method A described in ref ( 21 )). Candidate structures were then submitted to MOBCAL 33 to determine theoretical K 0 and CCS values (assuming helium as a bath gas) using the projection approximation (PA), the elastic hard sphere scattering (EHSS) and the trajectory (TM) methods (values are provided in the Supporting Information).…”

“…A pool of candidate structures with varying numbers of cis bond geometries of the polyene chain (including s-cis and s-trans conformations) for the lutein and zeaxanthin molecular and fragment ions were generated and optimized at the B3LYP/G-311G level . Energies of formation were calculated for all the obtained structures after a series of simulated annealing and geometry optimization cycles using AMBER03 force field in YASARA (analogous to method A described in ref ).…”

“…Analogous to this effect in peptides, here we expect that cis-trans geometrical isomerization of the carotenoid polyene chain will significantly influence the topology of these biological structures. In addition, the polyene chain of the carotenoids can exist in a large number of conformers originating from the s-cis/s-trans geometry associated with the single bonds of the conjugated system . The recent advent of trapped ion mobility spectrometry (TIMS) enables the study of small mobility ranges with high mobility resolution and is expected to permit a detailed characterization of the carotenoid geometrical isomers and conformers.…”