Unexpected discovery of estrone in the rotational spectrum of estradiol: a systematic investigation of a CP-FTMW spectrum.

We report the reinvestigation of the high-resolution rotational spectrum of estradiol. After removing the known spectral lines corresponding to three conformers of estradiol identified in the gas phase before, a large number of spectral lines remained unassigned in the spectrum. The observation of remaining lines is a common feature in spectra obtained by broadband rotational spectroscopy.

Rotational Signatures of Dispersive Stacking in the Formation of Aromatic Dimers.

The aggregation of aromatic species is dictated by inter- and intramolecular forces. Not only is characterizing these forces in aromatic growth important for understanding grain formation in the interstellar medium, but it is also imperative to comprehend biological functions. We report a combined rotational spectroscopic and quantum-chemical study on three homo-dimers, comprising of diphenyl ether, dibenzofuran, and fluorene, to analyze the influence of structural flexibility and the presence of heteroatoms on dimer formation.

Flexibility at the Fringes: Conformations of the Steroid Hormone β-Estradiol.

We present the accurate experimental structure of the steroid hormone β-estradiol obtained with high-resolution rotational spectroscopy under the solvent free, isolated, and cold conditions of a molecular jet. This is the first time that the rotational signature of a steroid hormone is reported. β-Estradiol is a primary female sex hormone and features a rigid steroidal ring system.

Aromatic embedding wins over classical hydrogen bonding - a multi-spectroscopic approach for the diphenyl ether-methanol complex.

Dispersion interactions are omnipresent in intermolecular interactions, but their respective contributions are difficult to predict. Aromatic ethers offer competing docking sites for alcohols: the ether oxygen as a well known hydrogen bond acceptor, but also the aromatic π system. The interaction with two aromatic moieties in diphenyl ether can tip the balance towards π binding.

High-Resolution Rotational Spectroscopy Study of the Smallest Sugar Dimer: Interplay of Hydrogen Bonds in the Glycolaldehyde Dimer.

Molecular recognition of carbohydrates plays an important role in nature. The aggregation of the smallest sugar, glycolaldehyde, was studied in a conformer-selective manner using high-resolution rotational spectroscopy. Two different dimer structures were observed.

Structure determination of trans-cinnamaldehyde by broadband microwave spectroscopy.

The rotational spectrum of trans-cinnamaldehyde ((E)-3-phenyl-2-propenal, C9H8O) was recorded by chirped-pulse Fourier transform microwave spectroscopy in the frequency range of 2-8.5 GHz. The odourant molecule is the essential component of cinnamon oil and causes the characteristic smell.

The shape of ibuprofen in the gas phase.

Ibuprofen's pain-relieving properties arise from its ability to physically block the active site of an enzyme, thus making its structural and conformational properties highly interesting. We here present a conformer-selective high-resolution broadband rotational spectroscopy study of gas-phase ibuprofen. The interpretation of the spectroscopic results is supported by quantum-chemical calculations.

Nuclear quadrupole coupling constants of two chemically distinct nitrogen atoms in 4-aminobenzonitrile.

The rotational spectrum of 4-aminobenzonitrile in the gas phase between 2 and 8.5 GHz is reported. Due to the two chemically distinct nitrogen atoms, the observed transitions showed a rich hyperfine structure.

Thermodynamic signature of substrates and substrate analogs binding to human blood group B galactosyltransferase from isothermal titration calorimetry experiments.

It has been observed earlier that human blood group B galactosyltransferase (GTB) hydrolyzes its donor substrate UDP-Galactose (UDP-Gal) in the absence of acceptor substrate, and that this reaction is promoted by the presence of an acceptor substrate analog, α-L-Fuc-(1,2)-β-D-3-deoxy-Gal-O-octyl (3DD). This acceleration of enzymatic hydrolysis of UDP-Gal was traced back to an increased affinity of GTB toward the donor substrate in the presence of 3DD. Herein, we present new thermodynamic data from isothermal titration calorimetry (ITC) on the binding of donor and acceptor substrates and analogs to GTB.