tailieunhanh - Báo cáo Y học: Soluble silk-like organic matrix in the nacreous layer of the bivalve Pinctada maxima A new insight in the biomineralization field

Nacre organic matrix has been conventionally classified as both water-soluble and water-insoluble ,basedonits solubility in aqueous solutions after decalcificationwith acid or EDTA. Some characteristics (aspartic acid-rich, silk-fibroin-like content) were specifically attributed to either one or the other. The comparative study on the technique of extraction (extraction with water alone vs. demineralization with EDTA) presented here, seems to reveal that this gen-erally accepted classification may need to be reconsidered | Eur. J. Biochem. 269 4994-5003 2002 FEBS 2002 doi Soluble silk-like organic matrix in the nacreous layer of the bivalve Pinctada maxima A new insight in the biomineralization field Lucilia Pereira-Mouries1. Maria-Jose Almeida1 3 Cristina Ribeiro3 Jean Peduzzi2 Michel Barthélemv2. Christian Milet1 and Evelyne Lopez1 1Laboratoire de Physiologie Generate et Comparee UMR CNRS 8572 Museum National d Histoire Naturelle Paris France 2Laboratoire de Chimie des Substances Naturelles ESA CNRS 8041 Museum National d Histoire Naturelle Paris France 3INEB - Instituto de Engenharia Biomedica Rua do Campo Alegre Porto Portugal Nacre organic matrix has been conventionally classified as both water-soluble and water-insoluble based on its solubility in aqueous solutions after decalcification with acid or EDTA. Some characteristics aspartic acid-rich silk-fibroin-like content were specifically attributed to either one or the other. The comparative study on the technique of extraction extraction with water alone vs. demineralization with EDTA presented here seems to reveal that this generally accepted classification may need to be reconsidered. Actually the nondecalcified soluble organic matrix extracted in ultra-pure water displays many of the characteristics of what until now has been called insoluble matrix . We present the results obtained on this extract and on a conventional EDTA-soluble matrix with various characterization methods fractionation by size-exclusion and anion-exchange HPLC amino acid analysis glycosaminoglycan and calcium quantification SDS PAGE and FTIR spectroscopy. We propose that the model for the interlamellar matrix sheets of nacre given by Nakahara In Biomineralization and Biological Metal Accumulation Westbroek P. deJong . eds 1983 pp. 225-230. Reidel Dordrecht Holland and Weiner and Traub Phil. Trans. R. Soc. Lond. B 1984 304 425-434 may no longer be valid. The most recent model proposed by Levi-Kalisman et al. J. .