Manchester Institute of Biotechnology, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom.
School of Earth and Environmental Sciences, The University of Manchester , Stopford Building, 99 Oxford Road, Manchester M13 9PG, United Kingdom.
J Proteome Res. 2018 Mar 2;17(3):1000-1013. doi: 10.1021/acs.jproteome.7b00648. Epub 2018 Feb 16.
Proteomic analyses are becoming more widely used in archeology not only due to the greater preservation of proteins in ancient specimens than DNA but also because they can offer different information, particularly relating to compositional preservation and potentially a means to estimate biological and geological age. However, it remains unclear to what extent different burial environments impact these aspects of proteome decay. Teeth have to date been much less studied than bone but are ideal to explore how proteins decay with time due to the negligible turnover that occurs in dentine relative to bone. We investigated the proteome variability and deamidation levels of different sections of molar teeth from archeological bovine mandibles as well as their mandibular bone. We obtained a greater yield of proteins from the crown of the teeth but did not find differences between the different molars analyzed within each mandible. We also obtained the best variety of protein from a well-preserved mandible that was not the youngest one in terms of chronological age, showing the influence of the preservation conditions on the final proteomic outcome. Intriguingly, we also noticed an increase in abundance levels of fetuin-A in biologically younger mandibles as reported previously, but the opposite trend in tooth dentine. Interestingly, we observed higher glutamine deamidation levels in teeth from the geologically oldest mandible despite it being the biologically youngest specimen, showing that the archeological age strongly impacts on the level of deamidations observed, much more so than biological aging. This indicates that the glutamine deamidation ratio of selected peptides may act as a good predictor of the relative geochronological age of archeological specimens.
蛋白质组分析在考古学中应用越来越广泛，不仅因为与 DNA 相比，古代标本中蛋白质的保存更为完好，还因为它们可以提供不同的信息，特别是与组成保存有关，并且可能是估计生物和地质年龄的一种手段。然而，不同的埋藏环境对蛋白质组降解的这些方面的影响程度仍不清楚。迄今为止，牙齿的研究比骨骼少得多，但由于牙本质相对于骨骼的更替率可忽略不计，因此是探索蛋白质随时间降解的理想选择。我们研究了来自考古牛下颚骨的磨牙不同部位以及其下颚骨的蛋白质组变异性和脱酰胺水平。我们从牙齿的牙冠中获得了更多的蛋白质，但没有发现每个下颚骨中不同磨牙之间的差异。我们还从一个保存完好的下颚骨中获得了最多样的蛋白质，而这个下颚骨不是按年代年龄计算的最年轻的一个，这表明保存条件对最终蛋白质组结果有影响。有趣的是，我们还注意到，正如之前报道的那样，在生物学上较年轻的下颚骨中，胎球蛋白-A 的丰度水平增加，但在牙本质中则相反。有趣的是，我们观察到，尽管最古老的地质下颚骨是生物学上最年轻的标本，但牙齿中的谷氨酰胺脱酰胺水平较高，这表明考古年龄对观察到的脱酰胺水平有强烈影响，比生物老化的影响大得多。这表明，所选肽的谷氨酰胺脱酰胺比可能是考古标本相对地质年代的良好预测指标。
