To promote the understanding of the relationship between emulsifying and molecular properties of proteins/peptides, intact beta-casein (betaCN) and its amphipathic fragment, i.e., betaCN (1-105/107) were dephosphorylated. Dephosphorylation was found not to change significantly their emulsifying properties. Since it is known that the structure of proteins can change upon adsorption onto an interface, the secondary structure of intact beta-casein, its amphipathic fragment, and their dephosphorylated forms, both in solution and after adsorption onto a hydrophobic teflon/water interface, were studied by far-UV circular dichroism spectroscopy. An increased content of secondary structure, especially alpha-helix, was found for all samples after adsorption onto teflon. Dephosphorylation increased the helix-forming propensity, especially for amphipathic fragment of beta-casein. No influence of the secondary structure properties on the emulsion-forming and -stabilizing properties was observed, but a relationship between the maximum surface load and the emulsion-stabilizing properties was found.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/s0300-9084(00)00210-8 | DOI Listing |
Int J Mol Sci
January 2025
A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, Leninskie Gory 1, Bld. 40, Moscow 119992, Russia.
Artificial peptides P4, A1 and A4 are homologous to amphipathic α-helical fragments of the influenza virus M1 protein. P4 and A4 contain the cholesterol recognition sequence CARC, which is absent in A1. As shown previously, P4 and A4 but not A1 have cytotoxic effects on some eukaryotic and bacterial cells.
View Article and Find Full Text PDFFront Mol Biosci
January 2025
Center for Biomolecular and Cellular Structure, Institute for Basic Science, Daejeon, Republic of Korea.
Huntington's disease (HD) is primarily caused by the aberrant aggregation of the N-terminal exon 1 fragment of mutant huntingtin protein (mHttex1) with expanded polyglutamine (polyQ) repeats in neurons. The first 17 amino acids of the N-terminus of Httex1 (N17 domain) immediately preceding the polyQ repeat domain are evolutionarily conserved across vertebrates and play multifaceted roles in the pathogenesis of HD. Due to its amphipathic helical properties, the N17 domain, both alone and when membrane-associated, promotes mHttEx1 aggregation.
View Article and Find Full Text PDFRes Sq
December 2024
Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
Nuclear deformation by osmotic shock or necrosis activates the cytosolic phospholipase A2 (cPla) nuclear shape sensing pathway, a key regulator of tissue inflammation and repair. Ca and inner nuclear membrane (INM) tension (T) are believed to mediate nucleoplasmic cPla activation. The concept implies that T persists long enough to stimulate cPla-INM adsorption.
View Article and Find Full Text PDFCell
April 2024
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA. Electronic address:
The membrane protein NINJ1 mediates plasma membrane rupture in pyroptosis and other lytic cell death pathways. Here, we report the cryo-EM structure of a NINJ1 oligomer segmented from NINJ1 rings. Each NINJ1 subunit comprises amphipathic (⍺1, ⍺2) and transmembrane (TM) helices (⍺3, ⍺4) and forms a chain of subunits, mainly by the TM helices and ⍺1.
View Article and Find Full Text PDFJ Phys Chem B
January 2024
Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
This work studied the membrane curvature generated by anchored proteins lacking amphipathic helices and intrinsic morphologies, including the Epsin N-terminal homology domain, intrinsically disordered C-terminal domain, and truncated C-terminal fragments, by using coarse-grained molecular dynamics simulations. We found that anchored proteins can stabilize the thermal undulation of membranes at a wavelength five times the protein's binding size. This proportional connection is governed by the membrane bending rigidity and protein density.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!