With their unique ability for substrate recognition and their sequence-specific self-assembly properties, peptides play an important role in controlling the mineralization of inorganic materials in natural systems and in controlling the assembly of soft materials into complex structures required for biological functions. Here we report the use of an engineered heptapeptide that can differentiate between the crystalline anhydrous polymorphs of calcium carbonate. This peptide contains the positively charged amino acid arginine as well as proline rather than the prototypical negatively charged aspartate or glutamate units. Its affinity to vaterite compared to aragonite was demonstrated by fluorescence microscopy using biotinylated peptides. Crystallization experiments in the presence of the vaterite-affine peptide afforded only vaterite, whereas a mutant peptide, where a proline residue was replaced by glycine, exclusively leads to the formation of calcite.
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http://dx.doi.org/10.1039/c4tb00160e | DOI Listing |
J Struct Biol
December 2024
Instituto Andaluz de Ciencias de la Tierra (IACT-CSIC), Armilla 18100, Granada, Spain. Electronic address:
The nacre formation process is a fascinating phenomenon involving mineral phase transformations, self-assembly processes, and protein-mineral interactions, resulting in a hierarchical structure that exhibits outstanding mechanical properties. However, this process is only partially known, and many aspects of nacre structure are not well understood, especially at the molecular scale. To understand the interplay between components-aragonite, protein and chitin-of the structure of nacre observed experimentally, we investigate the interactions of a peptide that is part of the protein lustrin A, identified in the nacreous layer of the shell of the abalone Haliotis rufescens, with the (001) crystal surface of aragonite and the chitin molecule.
View Article and Find Full Text PDFJ Gastrointest Surg
December 2024
Department of Radiation Oncology, Institute of Liver and Biliary Sciences, Delhi, India. Electronic address:
Background: India has a high incidence of gallstones, which can cause chronic inflammation and increase the risk of gallbladder cancer. Understanding the age and composition of gallstones can provide insights into their formation and growth. This study used ¹⁴C dating, FTIR, and metagenome analysis to explore the natural history, deposition rate, and microbial/chemical composition of gallstones.
View Article and Find Full Text PDFWater Res
December 2024
Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. Electronic address:
Calcium (Ca)-enhanced organic matter (OM) fouling of nanofiltration (NF) membranes leads to reduced flux during desalination and requires frequent cleaning. Fouling mechanisms are not fully understood, which limits the development of targeted fouling control methods. This study employed synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near-edge structure (XANES) spectroscopy to quantify the spatial distribution and mass of Ca deposition as well as changes in the Ca coordination environment characteristic of specific fouling mechanisms, respectively.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
School of Chemical Engineering, Guizhou Minzu University, Guiyang, China. Electronic address:
This paper reports a method for determining the carbonation rate (CR) of precipitated calcium carbonate (PCC) during carbonation process based on headspace gas chromatography technique. The method was carried out by simultaneously detecting the signal values of carbon dioxide and oxygen. Then the carbonation rate of precipitated calcium carbonate in the carbonation process can be calculated by the ratio (γ) of carbon dioxide to oxygen based on a new mathematical model.
View Article and Find Full Text PDFJ Funct Biomater
December 2024
Department of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria.
Background: Supragingival polishing is a crucial part of nonsurgical periodontal therapy. In recent years, air polishing has been used for this purpose, introducing different polishing powders. The purpose of the following study was to investigate the damage to the gingival margin during air polishing by an inexperienced operator.
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