Intercalation of sea urchin proteins in calcite: Study of a crystalline composite material

Journal Article · Fri Nov 02 00:00:00 EST 1990 · Science (Washington, D.C.); (USA)

DOI:https://doi.org/10.1126/science.250.4981.664· OSTI ID:5859811

Berman, A; Addadi, L; Leiserowitz, L; Weiner, S ^[1]; Kvick, A; Nelson, M ^[2]

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1. Weizmann Institute of Science, Rehovot (Israel)
2. Brookhaven National Laboratory, Upton, NY (USA)

Sea urchin skeletal elements are composed of single crystals of calcite. Unlike their synthetic counterparts, these crystals do not have well-developed cleavage and are consequently much more resistant to fracture. This phenomenon is due in part to the presence of acidic glycoproteins occluded within the crystals. By means of x-ray diffraction with synchrotron radiation, it is shown that the presence of the protein in synthetic calcite only slightly decreases the coherence length but significantly increases the angular spread of perfect domains of the crystals. In biogenic calcite, the coherence length is 1/3 to 1/4 as much as that in synthetic calcite and the angular spread is 20 to 50 times as wide. It is proposed that the presence of macromolecules concentrated at mosaic boundaries that are oblique to cleavage planes is responsible for the change in fracture properties. These results may be important in the material sciences, because of the unusual nature of this material, namely, a composite based on the controlled intercalation of macromolecules inside single-crystal lattices. 20 refs., 3 figs.

• OSTI ID: 5859811
• Journal Information: Science (Washington, D.C.); (USA), Vol. 250:4981; ISSN 0036-8075
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCITE
FRACTURE PROPERTIES
CLATHRATES
PROTEINS
CRYSTAL STRUCTURE
EXPERIMENTAL DATA
SEA URCHINS
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
AQUATIC ORGANISMS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
DATA
ECHINODERMS
INFORMATION
INVERTEBRATES
MECHANICAL PROPERTIES
MINERALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
550200* - Biochemistry