Structural studies of the Maillard reaction products of a protein using ion trap mass spectrometry

Tagami, Uno; Akashi, Satoko; Mizukoshi, Toshimi; Suzuki, Eiichiro; Hirayama, Kazuo

doi:10.1002/(sici)1096-9888(200002)35:2<131::aid-jms920>3.0.co;2-0

Cited by 44 publications

(31 citation statements)

References 20 publications

(21 reference statements)

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“…The FSA ligand could be located unambiguously on the re-side of the flavin ring (Figs. 2, B-D), with its fructosyl portion displaying a pyranose conformation, the most abundant form of fructosamines in solution (27). This finding confirms previous studies with stereospecific inhibitors adopting both furanose and pyranose conformations (28).…”

Section: Resultssupporting

confidence: 88%

Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

Collard

Zhang

Nemet

et al. 2008

Journal of Biological Chemistry

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Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6 Å resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12 Å deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.Fructosamines are formed by condensation of glucose with the amino group of amino acids or proteins. Fructosamines are formed spontaneously, i.e. non-enzymatically, at a rate that depends on temperature, sugar anomerization rate, concentration, and turnover rate of the target proteins. In medicine, protein-bound fructosamines (also named glycated proteins) have attracted much attention since their formation is increased in diabetes and taken to be in part responsible for diabetic complications. Fructosamines are relatively unstable compounds and are precursors for advanced glycation end products (AGEs), 5 some of which cause proteins cross-linking, extracellular matrix stiffening, and activation of the receptor for AGEs (RAGEs) (1, 2). As an example, the fructosamine-derived lysine-arginine cross-link glucosepane is to date the single major cross-link known to accumulate in human collagen in diabetes and aging (3).Several years ago our laboratory initiated a search for deglycating enzymes in soil organisms with the goal of finding enzymes that could deglycate proteins. In doing so we found enzymes with "amadoriase" activity toward low molecular weight substrates in soil samples, first in Pseudomonas sp. (4) and later in Aspergillus fumigatus (5-7). The latter turned out to have similar properties with the enzyme first published by Horiuchi et al. (8) under the name fructose amino acid oxidase (EC 1.5.3). Considerable work has since been published on these enzymes, which we are referring to in this work under the generic name fructosamine oxidases (FAOX).In addition to FAOX enzymes, two different families o...

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Section: Resultssupporting

confidence: 88%

Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

Collard

Zhang

Nemet

et al. 2008

Journal of Biological Chemistry

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“…33,34 Tryptophan oxidation products 35 and other age-related molecules can also develop during ageing of egg proteins. 36 This work aims to assess the effect that exposure to lighting in simulated indoor (museum) conditions has on Raman and fluorescence spectra of solid films of egg white and egg yolk. First, results of fluorescence spectroscopy are presented, which are followed by results of analysis using micro-Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Micro‐Raman and fluorescence spectroscopy for the assessment of the effects of the exposure to light on films of egg white and egg yolk

Osticioli

Nevin

Anglos

et al. 2008

J Raman Spectroscopy

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In this work, non-destructive techniques were employed for the spectrofluorimetric and micro-Raman differentiation of solid films of egg yolk and egg white as a function of exposure to light. Using both techniques it is possible to discriminate between the samples on the basis of composition and follow some chemical changes involved during the light-ageing of egg proteins and fatty acid esters. In egg white, fluorescence emission spectra highlighted the presence of multiple fluorophores, with an effective broadening of the fluorescence emissions following light exposure, ascribed to the partial oxidation and depletion of tryptophan; in the Raman spectrum of dark-aged egg white a peak at 758 cm −1 is ascribed to the vibrational mode of tryptophan, which is completely absent in the spectrum of samples exposed to light. Changes in the fluorescence of egg yolk following exposure to light are ascribed to the degradation of amino acids, cross-linking between amino acids and the formation of oxygenated triacylglycerides. These results are corroborated with Raman spectra of the light-exposed samples, which are associated with wavenumber shifts with respect to the dark-aged sample for the Amide I and for the characteristic carbonyl vibration at 1744 cm −1 ascribed to the oxidation of fatty acid esters.

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“…Glycation occurs via the Maillard reaction in which a reducing sugar reacts with an amino group on a protein, either at the NH 2 terminus or at the e-amino group of lysine residues (Tagami et al, 2000;Yeboah et al, 2004). This results in the formation of Amadori products for reaction with glucose (Bucala, 1996) or Heyns products for reaction with fructose (Suarez et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

The effect of peptide glycation on local secondary structure

Povey

Howard

Williamson

et al. 2008

Journal of Structural Biology

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Structural studies of the Maillard reaction products of a protein using ion trap mass spectrometry

Cited by 44 publications

References 20 publications

Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

Micro‐Raman and fluorescence spectroscopy for the assessment of the effects of the exposure to light on films of egg white and egg yolk

The effect of peptide glycation on local secondary structure

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