Protein diagenesis in Patella shells: implications for amino acid racemisation dating


Autoria(s): Ortiz Menéndez, José Eugenio; Gutiérrez-Zugasti, Igor; Torres Pérez-Hidalgo, Trinidad José; González-Morales, Manuel; Sánchez-Palencia González, Yolanda
Data(s)

2015

Resumo

Se analiza la racemización de aminoácidos en proteínas inter e intracristalinas en conchas de Patella y su utilización como herramienta geocronológica, fundamentalmente empleadas en yacimientos arqueológicos.The inter- and intra-crystalline fractions of Patella vulgata limpets recovered from archaeological sites in Northern Spain (covering Neolithic, Mesolithic, Magdalenian, Solutrean, and Aurignacian periods) were examined for amino acid composition and racemisation over time. The calcitic apex and rim areas of the shells were found to probably be composed of similar proteins, as the D/L values and amino acids were comparable and varied in the same way with increasing age; however, the mineral structures present in these areas differed. The aragonitic intermediate part of the shell showed a distinctly different amino acid composition and mineral structure. The main protein leaching from the inter-crystalline fraction occurred within the first 6000 yr after the death of the organism. In contrast, the intra-crystalline fraction — comprised of a different protein composition than the inter-crystalline fraction — appeared to behave as a closed system for at least 34 ka, as reflected by the lack of a significant decrease in the amino acid content; however, changes in the amino acid percentages occurred during this period. The concentration of aspartic acid remained almost constant with age both in inter- and intra-crystalline proteins, and its contribution to the total amino acid content increased with age at the expense of other amino acids such as glutamic acid, serine, glycine and alanine. Temperature is thought to play a key role in the amino acid racemisation of P. vulgata and could explain why in the localities belonging to the Gravettian and Solutrean period, which formed during relatively cold conditions, D/L values were similar to those detected in shells from sites formed during the Magdalenian.

Formato

application/pdf

Identificador

http://oa.upm.es/37736/

Idioma(s)

eng

Publicador

E.T.S.I de Minas y Energía

Relação

http://oa.upm.es/37736/1/INVE_MEM_2015_203220%281%29.pdf

http://www.sciencedirect.com/science/article/pii/S1871101415000217

info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quageo.2015.02.008

Direitos

http://creativecommons.org/licenses/by-nc-nd/3.0/es/

info:eu-repo/semantics/openAccess

Fonte

Quaternary Geochronology, ISSN 1871-1014, 2015, No. 27

Palavras-Chave #Química #Geología
Tipo

info:eu-repo/semantics/article

Artículo

PeerReviewed