title: Enantiomer-selective photolysis of cold gas-phase tryptophan in L-serine clusters with linearly polarized light.
abstract: Photostability of cold gas-phase tryptophan (Trp) enantiomers in L-serine (L-Ser) clusters at 8 K as a model for interstellar molecular clouds was examined using a tandem mass spectrometer containing a cold ion trap to investigate the hypothesis that homochirality in gas-phase Ser clusters promotes the enantiomeric enrichment of other amino acids via enantiomer-selective photolysis with linearly polarized light. In the UV excitation of heterochiral H(+) (L-Ser) 3(D-Trp), the CO2-eliminated product in the cluster was observed. In contrast, the photodissociation mass spectrum of homochiral H(+)(L-Ser)3(L-Trp) showed that photolysis of amino acids in the cluster did not occur due to the evaporation of L-Ser molecules. In the spectra of the homochiral H(+)(L-Ser) (L-Trp) and heterochiral H(+)(L-Ser) (D-Trp), the evaporation of L-Ser was the primary reaction pathway, and no difference between the L- and D-enantiomers was observed. The findings confirm that when 3 L-Ser units are present in the cluster, the photolytic decomposition of Trp is enantiomerically selective.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan, fujihara@c.s.osakafu-u.ac.jp.
authors.forename: Akimasa
authors.initials: A
authors.lastname: Fujihara
authors.forename: Naoto
authors.initials: N
authors.lastname: Maeda
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hayakawa
mesh_terms: D003080:Cold Temperature; D005740:Gases / Q000737:chemistry*; D008027:Light; D010782:Photolysis; D012694:Serine / Q000737:chemistry*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry; D014364:Tryptophan / Q000737:chemistry*; D014835:Volatilization
chemical_list: D005740:Gases; D012694:Serine; D014364:Tryptophan