J. Aizenberg et al., CRYSTAL PROTEIN INTERACTIONS STUDIED BY OVERGROWTH OF CALCITE ON BIOGENIC SKELETAL ELEMENTS, Journal of crystal growth, 142(1-2), 1994, pp. 156-164
A key parameter in the biological control of crystal formation is the
interaction of a group of acidic macromolecules with the mineral phase
. Here we study protein-calcite interactions using epitaxial overgrowt
h of synthetic calcite crystals under conditions in which local releas
e of occluded macromolecules from the biogenic substrate occurs. The m
acromolecules subsequently interact with the newly formed overgrown cr
ystals, resulting in modified calcite morphology. This novel method pr
ovides a means of mapping crystal-protein interactions under condition
s that minimally affect the conformational states of the acidic macrom
olecules. We show that proteins released from calcitic sponge spicules
and mollusc prisms specifically interact with {001} and {01l} faces o
f calcite, whereas proteins released from echinoderm skeletal elements
only interact with {01l} faces. The extent to which the overgrown cry
stals are affected by the proteins varies even in the same organism an
d within the same element, depending on the site and crystallographic
orientation of the skeletal elements.