Publication Date:
2008-11-01
Description:
Studies relating the magnesium (Mg) content of calcified skeletons to temperature often report unexplained deviations from the signature expected for inorganically grown calcite. These "vital effects" are believed to have biological origins, but mechanistic bases for measured offsets remain unclear. We show that a simple hydrophilic peptide, with the same carboxyl-rich character as that of macromolecules isolated from sites of calcification, increases calcite Mg content by up to 3 mole percent. Comparisons to previous studies correlating Mg content of carbonate minerals with temperature show that the Mg enhancement due to peptides results in offsets equivalent to 7 degrees to 14 degrees C. The insights also provide a physical basis for anecdotal evidence that organic chemistry modulates the mineralization of inorganic carbonates and suggest an approach to tuning impurity levels in controlled materials synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stephenson, A E -- DeYoreo, J J -- Wu, L -- Wu, K J -- Hoyer, J -- Dove, P M -- New York, N.Y. -- Science. 2008 Oct 31;322(5902):724-7. doi: 10.1126/science.1159417.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA. aestephe@vt.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18974348" target="_blank"〉PubMed〈/a〉
Keywords:
Calcification, Physiologic
;
Calcium/analysis
;
Calcium Carbonate/*chemistry
;
Crystallization
;
Geologic Sediments/chemistry
;
Magnesium/*analysis
;
Microscopy, Atomic Force
;
Peptides/*chemistry
;
Temperature
;
Thermodynamics
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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