The antifreeze activity of a type-III antifreeze protein (AFP) expressed in ocean pout (Zoarces americanus) is compared with that of a specific mutant (T18N) using all-atom molecular dynamics simulations. The antifreeze activity of the mutant is only 10% of the wild-type AFP. The results from this simulation study revealed the following insights into the mechanism of antifreeze action by type-III AFPs. The AFP gets adsorbed to the advancing ice front due to its hydrophobic nature. A part of the hydrophobicity is caused by the presence of clathrate structure of water molecules near the ice-binding surface (IBS). The mutation in the AFP disrupts this structure and thereby reduces the ability of the mutant to adsorb to the ice-water interface leading to the loss of antifreeze activity. The mutation, however, has no effect on the ability of the adsorbed protein to bind to the growing ice phase. Simulations also revealed that all surfaces of the protein can bind to the ice phase, although the IBS is the preferred surface.
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http://dx.doi.org/10.1021/acs.langmuir.0c00065 | DOI Listing |
Biomacromolecules
December 2024
DISFARM, Department of Pharmaceutical Sciences, "A. Marchesini" General and Organic Chemistry Section, Università degli Studi di Milano, Via Venezian 21, Milan 20133, Italy.
In nature, organisms living in extreme environmental conditions produce antifreeze proteins (AFPs) that prevent the growth of ice crystals and depress the freezing point of body fluids. In this study, three different peptides derived from the N-terminal sequence of the helical type I AFP HPLC6, along with a stapled derivative produced via on-resin microwave-assisted copper(I)-catalyzed azide-alkyne cycloaddition, were conjugated to gold nanoparticles. The aim of decorating the surface of the nanoparticles with multiple copies of the peptides was to combine the ice-binding capability of the peptides with the size of a nanoparticle, thus, mimicking the protein bulkiness to enhance the peptide antifreeze activity.
View Article and Find Full Text PDFExtremophiles
December 2024
School of Life Sciences, University of Nevada Las Vegas, Las Vegas, USA.
Among the many ice-binding proteins (IBPs) found in microorganisms (bacteria, archaea, fungi and algae), the canonical DUF3494 beta-barrel type is the most common. Until now, little variation has been found in this structure: an initial coil leads into an alpha helix that directs the following coils into a reverse stack, with the final coil ending up next to the initial coil. Here, I show that there exist many bacterial proteins whose AlphaFold-predicted structures deviate from the DUF3494 structure so that they are not recognized as belonging to an existing DUF or Pfam family.
View Article and Find Full Text PDFAMB Express
November 2024
Graduate Program of Microbial Biology, Institute of Biology, University of Brasília, Brasília, Brazil.
Ethylene glycol (EG) is a versatile molecule produced in the petrochemical industry and is widely used to manufacture plastic polymers, anti-freeze, and automotive fluids. Biotechnological production of EG from xylose, a pentose present in lignocellulose biomass hydrolysates, has been achieved by the engineering of bacteria, such as Escherichia coli and Enterobacter cloacae, and the yeast Saccharomyces cerevisiae with synthetic pathways. In the present work, the Dahms pathway was employed to construct Komagataella phaffii strains capable of producing EG from xylose.
View Article and Find Full Text PDFBioact Mater
February 2025
The Laboratory for Advanced Functional/Medicinal Polymers & Smart Drug Delivery Technologies, The Wolfson Faculty of Chemical Engineering, Technion-Israel Institute of Technology, Haifa, 3200003, Israel.
J Chem Phys
October 2024
Faculty of Chemistry, Department of Physical Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
In 2012, the molecular structure of a new, broad class of ice-binding proteins, classified as "domain of unknown function" (DUF) 3494, was described for the first time. These proteins have a common tertiary structure and are characterized by a very wide spectrum of antifreeze activity (from weakly active to hyperactive). The ice-binding surface (IBS) region of these molecules differs significantly in its structure from the IBS of previously known antifreeze proteins (AFPs), showing a complete lack of regularity and high hydrophilicity.
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