Tools for the identification of bacteria are of great importance especially for taxonomical and medical purposes. In the case of fluorescent pseudomonads a quick and unambiguous identification is possible by methods that are referred to as "siderotyping". All of them are based upon the characterization of the bacterial siderophores or the receptors expressed for the uptake of these compounds. Different microbiological and bioanalytical tests that are accurate, rapid and easy to use will be described.

The structure of the alkylzinc-tetramethylethyl-enediamine (TMEDA) cluster cation 3 has been determined in the gas phase by a combination of tandem mass spectrometry, infrared multiphoton dissociation (IRMPD) spectroscopy, and DFT calculations. Both sets of experimental results establish the existence of a strongly stabilizing interaction of TMEDA with the zinc cation. High-level DFT calculations on the alkylzinc-TMEDA cluster cation 3 allowed the identification of two low energy conformers, each featuring a four-coordinate zinc atom with a bidentate TMEDA ligand, and internal coordination from the carbonyl group of the Boc group to zinc. The experimental IRMPD spectrum is reproduced with an appropriately weighted combination of the IR spectra of the two conformers identified by theory. DFT calculations on the structure of the alkylzinc halide 2 with coordinated TMEDA using the PCM model of water solvent suggest that TMEDA can promote ionization of the zinc-iodine bond in organozinc iodides under aqueous conditions, providing a credible explanation for the role of TMEDA in stabilizing the carbon-zinc bond. Reaction of the serine-derived iodide 1 with aryl iodides "on water", promoted by nano zinc in the presence of PdCl(2)(Amphos)(2) (5 mol %) and TMEDA, leads to the formation of protected phenylalanine derivatives 4 in reasonable yields. In the case of ortho-substituted aryl iodides and aryl iodides that are solids at room temperature, conducting the reaction at 65 °C gives improved results. In all cases, the product 5 of reductive dimerization of the iodide 1 is also isolated.

The gas-phase structures of a series of potassiated tertiary amino acids have been systematically investigated using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser, ion mobility spectrometry (IMS), and computational modeling. The examined analytes comprise a set of five linear N,N-dimethyl amino acids derived from N,N-dimethyl glycine and three cyclic N-methyl amino acids including N-methyl proline. The number of methylene groups in either the alkyl chain of the linear members or in the ring of the cyclic members of the series is gradually varied. The spectra of the cyclic potassiated molecular ions are similar and well resolved, whereas the clear signals in the respective spectra of the linear analytes increasingly overlap with longer alkyl chains. Measured IRMPD spectra are compared to spectra calculated at the B3LYP/6-311++G(2d,2p) level of theory to identify the structures present in the experimental studies. On the basis of these experiments and calculations, all potassiated molecular ions of this series adopt salt bridge structures in the gas phase, involving bidentate coordination of the potassium cation to the carboxylate moiety. The assigned salt bridge structures are predicted to be the global minima on the potential energy surfaces. IMS cross-section measurements of the potassiated systems show a monotonic increase with growing system size, suggesting that the precursor ions adopt the same type of structure and comparisons between experimental and theoretical cross sections are consistent with salt bridge structures and the IRMPD results.

The structure elucidation of the cyclic (lactonic) forms of the pyoverdins with a succinamide side chain originally produced by the closely related species Pseudomonas syringae and P. cichorii is reported. Mass spectrometry and nuclear magnetic resonance analyses as well as the determination of the configuration of the amino acids after degradation indicate that these two pyoverdins differ only by the replacement of the first in-chain serine by glycine. The pyoverdins of P. syringae and P. cichorii and the dihydropyoverdin of P. syringae can be used by both species as siderophores.

We present an integrated approach for investigating the topology of proteins through native mass spectrometry (MS) and cross‐linking/MS, which we applied to the full‐length wild‐type p53 tetramer. For the first time, the two techniques were combined in one workflow to obtain not only structural insight in the p53 tetramer, but also information on the cross‐linking efficiency and the impact of cross‐linker modification on the conformation of an intrinsically disordered protein (IDP). P53 cross‐linking was monitored by native MS and as such, our strategy serves as a quality control for different cross‐linking reagents. Our approach can be applied to the structural investigation of various protein systems, including IDPs and large protein assemblies, which are challenging to study by the conventional methods used for protein structure characterization.