Assessing the Extent of Bone Degradation Using Glutamine Deamidation in Collagen

• Published in: Analytical chemistry (Washington) Vol. 84; no. 21; pp. 9041 - 9048
• Main Authors: Wilson, Julie, van Doorn, Nienke L, Collins, Matthew J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 06.11.2012
• Subjects: Amino Acid Sequence; Analytical chemistry; Bone and Bones - metabolism; Chemistry; Collagen; Collagen - chemistry; Collagen - metabolism; Deamination; Exact sciences and technology; Genetic algorithms; Glutamine - metabolism; Humans; Isotopes; Mass spectrometry; Molecular Sequence Data; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Peptides; Spectrometric and optical methods; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Shift; Glutamic acid; Age estimation; Peptides; Sample; Use; Matrix assisted laser desorption ionization; Method; Protein; Degradation; Genetic algorithm; Residue; Collagen; DNA; Distribution; Peak; Mass spectrometry; Glutamine
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac301333t

Collagen peptides are analyzed using a low-cost, high-throughput method for assessing deamidation using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). For each chosen peptide, the theoretical distribution is calculated and the measured distribution for each sample compared with this to determine the extent of glutamine deamidation. The deamidation of glutamine (Q) to glutamic acid (E) results in a mass shift of +0.984 Da. Thus, from the resolution of our data, the second peak in the isotope distribution for a peptide containing one glutamine residue coincides with the first peak of the isotope distribution for the peptide in which the residue is deamidated. A genetic algorithm is used to determine the extent of deamidation that gives the best fit to the measured distribution. The method can be extended to peptides containing more than one glutamine residue. The extent of protein degradation assessed in this way could be used, for example, to assess the damage of collagen, and screen samples for radiocarbon dating and DNA analysis.