Infrared spectra and molar absorption coefficients of the 20 alpha amino acids in aqueous solutions in the spectral range from 1800 to 500cm−1

Wolpert, Martina; Hellwig, Petra

doi:10.1016/j.saa.2005.08.025

Cited by 266 publications

(243 citation statements)

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“…Signals between ϳ1570 and 1520 cm Ϫ1 , the so-called amide II range, include contributions from the coupled C-N stretching and N-H bending vibrations of the backbone. For the contributions of individual amino acids the most prominent signals are found at positions higher than 1710 cm Ϫ1 , where the CϭO group of protonated aspartic and glutamic acid side chains are expected depending on their hydrogen bonding environment (34 -36 arginine (35,36). No pronounced menaquinone signals can be discriminated, indicating, that the preparation is essentially menaquinone-free.…”

Section: Kinetic Characteristics Of the Mutants-thementioning

confidence: 97%

Differences in Protonation of Ubiquinone and Menaquinone in Fumarate Reductase from Escherichia coli

Maklashina

Hellwig

Rothery

et al. 2006

Journal of Biological Chemistry

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Escherichia coli quinol-fumarate reductase operates with both natural quinones, ubiquinone (UQ) and menaquinone (MQ), at a single quinone binding site. We have utilized a combination of mutagenesis, kinetic, EPR, and Fourier transform infrared methods to study the role of two residues, Lys-B228 and Glu-C29, at the quinol-fumarate reductase quinone binding site in reactions with MQ and UQ. The data demonstrate that Lys-B228 provides a strong hydrogen bond to MQ and is essential for reactions with both quinone types. Substitution of Glu-C29 with Leu and Phe caused a dramatic decrease in enzymatic reactions with MQ in agreement with previous studies, however, the succinate-UQ reductase reaction remains unaffected. Elimination of a negative charge in Glu-C29 mutant enzymes resulted in significantly increased stabilization of both UQ . and MQ . semiquinones. The data presented here suggest similar hydrogen bonding of the C1 carbonyl of both MQ and UQ, whereas there is different hydrogen bonding for their C4 carbonyls. The differences are shown by a single point mutation of Glu-C29, which transforms the enzyme from one that is predominantly a menaquinol-fumarate reductase to one that is essentially only functional as a succinate-ubiquinone reductase. These findings represent an example of how enzymes that are designed to accommodate either UQ or MQ at a single Q binding site may nevertheless develop sufficient plasticity at the binding pocket to react differently with MQ and UQ.Facultative anaerobic bacteria and lower eukaryotes adapt their metabolism in response to environmental changes. An important aspect of this adaptability is that many can synthesize both ubiquinone (UQ) 4 and menaquinone (MQ). Quinone biosynthesis and relative concentration is regulated by growth conditions and oxygen supply with UQ and MQ being the primary quinone under aerobic and anaerobic conditions, respectively (1). Membrane-bound bacterial enzymes that utilize quinones as substrates can often catalyze redox reactions with both UQ and MQ. Membrane-bound quinol-fumarate reductase (QFR) in Escherichia coli is an example of an enzyme that can readily use both types of quinones and shows high menaquinolfumarate and succinate-quinone reductase activities (2). QFR serves as a terminal reductase in the anaerobic bacterial respiratory chain by catalyzing the menaquinol-fumarate reductase reaction (3). When genetically manipulated to allow its expression under aerobic conditions, QFR efficiently replaces succinateubiquinone reductase (SQR) in aerobic metabolism and cell growth by catalyzing ubiquinone reduction from succinate (4).Membrane-bound QFR from E. coli is a four subunit complex, and its x-ray structure has been solved (5-9). The FrdA and FrdB subunits comprise the soluble component that contains a dicarboxylate substrate binding site, a covalently bound FAD, and three linearly arranged iron-sulfur centers (5-7). The membrane-spanning hydrophobic subunits FrdC and FrdD are necessary to anchor the soluble the FrdAB domain to the membrane an...

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Section: Kinetic Characteristics Of the Mutants-thementioning

confidence: 97%

Differences in Protonation of Ubiquinone and Menaquinone in Fumarate Reductase from Escherichia coli

Maklashina

Hellwig

Rothery

et al. 2006

Journal of Biological Chemistry

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“…In the experiment performed by M. Wolpert et al [4], infrared vibrational spectra and band assignments for all typical amino acids in aqueous solutions within 500…1800 cm -1 spectral range were carried out. Implementation of Raman spectroscopy for the solid Glutamine analysis was investigated only in few previous studies [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

Raman study of L-Asparagine and L-Glutamine molecules adsorbed on aluminum films in a wide frequency range

Golichenko¹

2017

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. Using micro-Raman spectroscopy, a detailed study of vibrational spectra of L-Asparagine and L-Glutamine amino acids adsorbed on aluminum foils were carried out within the frequency range 80…3500 cm -1 under different excitation wavelengths. On the basis of detailed analysis of Raman spectra of the mentioned above amino acids and data of DFT-calculations of normal modes and isotopic substitution for these analytes available in literature, interpretation of amino acids vibrational bands were performed. The polarized Raman spectra of studied amino acids indicate different ordering of polycrystalline structure in distinct spots on the sample. The most significant variations of ratios between polarized bands are principally observed for deformation vibrations of NH 2 , COO -and CH 2 groups within entire "fingerprint" range and valence vibrations of CC and CN bonds within the range 1000…1100 cm -1 .

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“…Although the data in our manuscript only covered qualitative analysis a more detailed quantitative analysis in terms of monitoring the conversion percentage is necessary. These experiments are in progress in our lab [31][32][33][34][35][36][37][38][39][40][41].…”

Section: Resultsmentioning

confidence: 93%

Real Time Monitoring the Maillard Reaction Intermediates by HPLC- FTIR

Ioannou¹,

Varotsis²

2016

J Phys Chem Biophys

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Infrared spectra and molar absorption coefficients of the 20 alpha amino acids in aqueous solutions in the spectral range from 1800 to 500cm−1

Cited by 266 publications

References 50 publications

Differences in Protonation of Ubiquinone and Menaquinone in Fumarate Reductase from Escherichia coli

Differences in Protonation of Ubiquinone and Menaquinone in Fumarate Reductase from Escherichia coli

Raman study of L-Asparagine and L-Glutamine molecules adsorbed on aluminum films in a wide frequency range

Real Time Monitoring the Maillard Reaction Intermediates by HPLC- FTIR

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