Control of Calcite Crystal Morphology by a Peptide Designed To Bind to a Specific Surface
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- 作者：Daniel B. DeOliveira and Richard A. Laursen
- 刊名：Journal of the American Chemical Society
- 出版年：1997
- 出版时间：November 5, 1997
- 年：1997
- 卷：119
- 期：44
- 页码：10627 - 10631
- 全文大小：140K
- 年卷期：v.119,no.44(November 5, 1997)
- ISSN：1520-5126
文摘
Many organisms contain proteins which regulate the size and shapeof inorganic crystals in their skeletalelements, most likely through specific protein-crystal surfaceinteractions. As a model for better understandingsuch control of crystal morphology, an 
-helical peptide (CBP1) wassynthesized having an array of aspartyl residuesdesigned to bind to the {1
0} prism faces of calcite.When added to a saturated solution of calciumbicarbonatecontaining rhombohedral calcite seed crystals, CBP1 had a remarkableeffect on subsequent calcite growth, dependingon growth conditions. At 3 
C, where CBP1 is 89% helical, thecrystals assumed a prismatic habit, with growthcontinuing along the c-axis, but inhibited parallel to thec-axis and prism faces; at 25 C, where CBP1 islargelyunstructured, studded crystals formed, resulting from epitaxial growthoff each of the six rhombohedral surfaces.Other acidic peptides also caused similar epitaxial growth.These results suggest that the helical form of thepeptiderecognizes specific crystal surface characteristics, whereas theunfolded form acts nonspecifically as a polyanion.When the peptide was removed from the growth medium containingeither type of crystal, regrowth of {104}rhombohedral surfaces ensued at the expense of the nonrhombohedralsurfaces. These results represent the firstexample of conformation-dependent control of calcite crystal growth bya peptide of defined secondary structure.
-helical peptide (CBP1) wassynthesized having an array of aspartyl residuesdesigned to bind to the {10} prism faces of calcite.When added to a saturated solution of calciumbicarbonatecontaining rhombohedral calcite seed crystals, CBP1 had a remarkableeffect on subsequent calcite growth, dependingon growth conditions. At 3 C, where CBP1 is 89% helical, thecrystals assumed a prismatic habit, with growthcontinuing along the c-axis, but inhibited parallel to thec-axis and prism faces; at 25 C, where CBP1 islargelyunstructured, studded crystals formed, resulting from epitaxial growthoff each of the six rhombohedral surfaces.Other acidic peptides also caused similar epitaxial growth.These results suggest that the helical form of thepeptiderecognizes specific crystal surface characteristics, whereas theunfolded form acts nonspecifically as a polyanion.When the peptide was removed from the growth medium containingeither type of crystal, regrowth of {104}rhombohedral surfaces ensued at the expense of the nonrhombohedralsurfaces. These results represent the firstexample of conformation-dependent control of calcite crystal growth bya peptide of defined secondary structure.