1.Metabolomic analysis of riboswitch containing E. coli recombinant expression system.
Muhamadali H1, Xu Y1, Morra R2, Trivedi DK1, Rattray NJ1, Dixon N2, Goodacre R1. Mol Biosyst. 2016 Jan 26;12(2):350-61. doi: 10.1039/c5mb00624d.
In this study we have employed metabolomics approaches to understand the metabolic effects of producing enhanced green fluorescent protein (eGFP) as a recombinant protein in Escherichia coli cells. This metabolic burden analysis was performed against a number of recombinant expression systems and control strains and included: (i) standard transcriptional recombinant expression control system BL21(DE3) with the expression plasmid pET-eGFP, (ii) the recently developed dual transcriptional-translational recombinant expression control strain BL21(IL3), with pET-eGFP, (iii) BL21(DE3) with an empty expression plasmid pET, (iv) BL21(IL3) with an empty expression plasmid, and (v) BL21(DE3) without an expression plasmid; all strains were cultured under various induction conditions. The growth profiles of all strains together with the results gathered by the analysis of the Fourier transform infrared (FT-IR) spectroscopy data, identified IPTG-dependent induction as the dominant factor hampering cellular growth and metabolism, which was in general agreement with the findings of GC-MS analysis of cell extracts and media samples.
2.Biogenic Nanoparticles from Schwanniomyces occidentalis NCIM 3459: Mechanistic Aspects and Catalytic Applications.
Mohite P1, Apte M1, Kumar AR1, Zinjarde S2. Appl Biochem Biotechnol. 2016 Feb 22. [Epub ahead of print]
When cells of Schwanniomyces occidentalis NCIM 3459 were incubated with 1 mM tetrachloroauric acid (HAuCl4) or silver nitrate (AgNO3), cell-associated nanoparticles were obtained. Their presence was confirmed by scanning electron microscope observations. The cell-free supernatant (CFS) of the yeast mediated the synthesis of gold nanoparticles. On account of the difficulties associated with the use of cell-bound nanoparticles, further work was restricted to extracellular nanoparticles. It was hypothesized that the CFS contained thermostable biomolecule(s) that mediated metal reduction reactions. Extraction of the CFS with chloroform/methanol (2:1) and subsequent separation by preparative thin layer chromatography led to the activity-guided purification of a glycolipid. The glycolipid was hydrolyzed and the glycone (glucose) and aglycone components (palmitic acid and oleic acid) were identified by gas chromatography-mass spectrometry. The purified glycolipid mediated the synthesis of gold and silver nanoparticles that were characterized by using an X-ray diffractometer and transmission electron microscope (TEM).
3.Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4 ] Complexes.
Sharma HK1, Gonzalez PE1, Craig AL1, Chakrabarty S1, Metta-Magaña A1, Pannell KH2. Chemistry. 2016 Apr 25. doi: 10.1002/chem.201600810. [Epub ahead of print]
Compound Et3 SiOCH2 NMe2 transfers Me2 NCH2 to R2 NH (R2 =Et2 , PhMe, [Cr(η6 -C6 H5 )(CO)3 ]Me, PhH) to form previously unknown diaminomethanes, Me2 NCH2 NR2 and, in the case of R2 =PhH, the triamine Me2 NCH2 N(Ph)CH2 NMe2 . The diaminomethanes exhibit an unreported disproportionation to a mixture of (R2 N)2 CH2 , (Me2 N)2 CH2 , and Me2 NCH2 NR2 , which can be trapped as their [Mo(CO)4 (diamine)] complexes. Whereas PhMeNCH2 NMe2 is a labile material, the metal-substituted ([(η6 -C6 H5 )Cr(CO)3 ]MeNCH2 NMe2 is a stable material. The triamine Me2 NCH2 N(Ph)CH2 NMe2 is unstable with respect to transformation to 1,3,5-triphenyltriazine, but is readily trapped as the bidentate-triamineMo(CO)4 . All metal complexes were characterized by single-crystal X-ray diffraction.
4.Oxidative Dimerization of Triarylamines Promoted by WCl6, Including the Solid State Isolation and the Crystallographic Characterization of a Triphenylammonium Salt.
Bortoluzzi M1, Marchetti F2, Pampaloni G2, Pinzino C3, Zacchini S4. Inorg Chem. 2016 Jan 19;55(2):887-93. doi: 10.1021/acs.inorgchem.5b02392. Epub 2015 Dec 23.
The triphenylammonium salt [NHPh3][WCl6], 1, and the product of the C-C dimerization of triphenylamine, Ph2N(C6H4)2NPh2, 2, were afforded from the reaction between WCl6 and NPh3 in CH2Cl2. Compound 2 was isolated in 43% yield upon hydrolysis of the reaction mixture. The X-ray structure of 1 provides the first crystallographic characterization of the triphenylammonium ion. Combined EPR and DFT studies gave insight into the reaction mechanism, and allowed the identification of WCl5···[Cl(C6H4)NPh2] as a presumable key intermediate. The reactions of WCl6 with 4-bromotriphenylamine, 4,4'-dimethyltriphenylamine, 9-phenylcarbazole, followed by hydrolytic treatment, led to the dimerization products 3-6, in admixture with variable amounts of the parent amines. N,N,N',N'-tetrakis(4-bromophenyl)-[1,1'-biphenyl]-4,4'-diamine, 3, was isolated in 60% yield from the reaction of WCl6 with 4,4'-dibromotriphenylamine.