Dataset Information

Dispersion-Bound Isolated Dimers in the Gas Phase: Observation of the Shortest Intermolecular CH⋅⋅⋅H-C Distance via Stimulated Raman Spectroscopy.

ABSTRACT: The triphenylmethane and all-meta tert-butyl triphenylmethane dimers, (TPM)₂ and (T ^t BuPM)₂ , respectively, were studied with ionization loss stimulated Raman spectroscopy in molecular beam experiments to resolve structure sensitive vibrations. This answers the question whether the recently reported linear head-to-head arrangement in (T ^t BuPM)₂ results from crystal packing or prevails also in the gas phase, and therefore must result from extraordinarily strong London dispersion (LD) interactions. Our study clearly demonstrates that the head-to-head arrangement is maintained even under isolated molecular beam conditions in the absence of crystal packing effects. The central Raman-active aliphatic C-D vibration of appropriately deuterated (T ^t BuPM)₂ associated with an unusually short C-D⋅⋅⋅D-C distance exhibits a strong blue-shift compared to the undisturbed case. As the LD stabilizing tert-butyl groups are absent in (TPM)₂ , it displays an approximately S₆ -symmetric tail-to-tail arrangement.

SUBMITTER: Maue D

PROVIDER: S-EPMC8252503 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

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Dispersion-Bound Isolated Dimers in the Gas Phase: Observation of the Shortest Intermolecular CH⋅⋅⋅H-C Distance via Stimulated Raman Spectroscopy.

Maué Dominique D Strebert Patrick H PH Bernhard Dominic D Rösel Sören S Schreiner Peter R PR Gerhards Markus M

Angewandte Chemie (International ed. in English) 20210501 20

The triphenylmethane and all-meta tert-butyl triphenylmethane dimers, (TPM)2 and (T t BuPM)2 , respectively, were studied with ionization loss stimulated Raman spectroscopy in molecular beam experiments to resolve structure sensitive vibrations. This answers the question whether the recently reported linear head-to-head arrangement in (T t BuPM)2 results from crystal packing or prevails also in the gas phase, and therefore must result from e ...[more]

PMID: 33709534

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Project description:UnlabelledBacteriophytochrome photoreceptors (BphPs) and their cognate response regulators make up two-component signal transduction systems which direct bacteria to mount phenotypic responses to changes in environmental light quality. Most of these systems utilize single-domain response regulators to transduce signals through unknown pathways and mechanisms. Here we describe the photocycle and autophosphorylation kinetics of RtBphP1, a red light-regulated histidine kinase from the desert bacterium Ramlibacter tataouinensis RtBphP1 undergoes red to far-red photoconversion with rapid thermal reversion to the dark state. RtBphP1 is autophosphorylated in the dark; this activity is inhibited under red light. The RtBphP1 cognate response regulator, the R. tataouinensis bacteriophytochrome response regulator (RtBRR), and a homolog, AtBRR from Agrobacterium tumefaciens, crystallize unexpectedly as arm-in-arm dimers, reliant on a conserved hydrophobic motif, hFWAhL (where h is a hydrophobic M, V, L, or I residue). RtBRR and AtBRR dimerize distinctly from four structurally characterized phytochrome response regulators found in photosynthetic organisms and from all other receiver domain homodimers in the Protein Data Bank. A unique cacodylate-zinc-histidine tag metal organic framework yielded single-wavelength anomalous diffraction phases and may be of general interest. Examination of the effect of the BRR stoichiometry on signal transduction showed that phosphorylated RtBRR is accumulated more efficiently than the engineered monomeric RtBRR (RtBRRmon) in phosphotransfer reactions. Thus, we conclude that arm-in-arm dimers are a relevant signaling intermediate in this class of two-component regulatory systems.ImportanceBphP histidine kinases and their cognate response regulators comprise widespread red light-sensing two-component systems. Much work on BphPs has focused on structural understanding of light sensing and on enhancing the natural infrared fluorescence of these proteins, rather than on signal transduction or the resultant phenotypes. To begin to address this knowledge gap, we solved the crystal structures of two single-domain response regulators encoded by a region immediately downstream of that encoding BphPs. We observed a previously unknown arm-in-arm dimer linkage. Monomerization via deletion of the C-terminal dimerization motif had an inhibitory effect on net response regulator phosphorylation, underlining the importance of these unusual dimers for signal transduction.

Dataset Information

Dispersion-Bound Isolated Dimers in the Gas Phase: Observation of the Shortest Intermolecular CH⋅⋅⋅H-C Distance via Stimulated Raman Spectroscopy.

Publications

Dispersion-Bound Isolated Dimers in the Gas Phase: Observation of the Shortest Intermolecular CH⋅⋅⋅H-C Distance via Stimulated Raman Spectroscopy.

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