A novel toxin was identified, purified and characterized from the venom of the Mexican scorpion Hadrurus gertschi (abbreviated HgeTx1). It has a molecular mass of 3950 atomic mass units (a.m.u.) and contains 36 amino acids with four disulfide bridges established between Cys1-Cys5, Cys2-Cys6, Cys3-Cys7 and Cys4-Cys8. It blocks reversibly the Shaker B K(+)-channels with a Kd of 52nM. HgeTx1 shares 60%, 45% and 40% sequence identity, respectively, with Heterometrus spinnifer toxin1 (HsTX1), Scorpio maurus K(+)-toxin (maurotoxin) and Pandinus imperator toxin1 (Pi1), all four-disulfide bridged toxins. It is 57-58% identical with the other scorpion K(+)-channel toxins that contain only three disulfide bridges. Sequence comparison, chain length and number of disulfide bridges analysis classify HgeTx1 into subfamily 6 of the alpha-KTx scorpion toxins (systematic name: alpha-KTx 6.14).
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http://dx.doi.org/10.1016/j.toxicon.2006.08.009 | DOI Listing |
Nat Commun
January 2025
Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du sud 4-5, L7.07.07, Louvain-la-Neuve, Belgium.
The SARS-CoV-2 spike protein's membrane-binding domain bridges the viral and host cell membrane, a critical step in triggering membrane fusion. Here, we investigate how the SARS-CoV-2 spike protein interacts with host cell membranes, focusing on a membrane-binding peptide (MBP) located near the TMPRSS2 cleavage site. Through in vitro and computational studies, we examine both primed (TMPRSS2-cleaved) and unprimed versions of the MBP, as well as the influence of its conserved disulfide bridge on membrane binding.
View Article and Find Full Text PDFChembiochem
December 2024
Friedrich-Schiller-Universitat Jena, Institute of Physical Chemistry, GERMANY.
Heme is involved in many critical processes in pathogenic bacteria as iron acquisition by these microorganisms is achieved by either direct uptake of heme or use of heme-binding proteins called hemophores. Exploring the underlying mechanisms on a molecular level can open new avenues in understanding the host-pathogen interactions. Any imbalance of the heme concentration has a direct impact on the bacterial growth and survival.
View Article and Find Full Text PDFActa Biochim Biophys Sin (Shanghai)
December 2024
Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China.
The use of green fluorescence protein (GFP) has advanced numerous areas of life sciences. An ultra-thermostable GFP (TGP), engineered from a coral GFP, offers potential advantages over traditional jellyfish-derived GFP because of its high stability. However, owing to its later discovery, TGP lacks the extensive toolsets available for GFP, such as heavy chain-only antibody binders known as nanobodies.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Proteomics, Bioanalytics Department, Nestlé Institute of Food Safety & Analytical Sciences, Nestlé Research, Lausanne, Switzerland.
Protein biomarker discovery in human biological fluids has greatly developed over the past two decades thanks to technological advances allowing deeper proteome coverage and higher sample throughput, among others. While blood samples are most commonly investigated due to their moderate ease of collection and high information content, other biological fluids such as cerebrospinal fluid (CSF) and urine are highly relevant for specific pathologies, such as brain and urologic diseases, respectively. Independently of the biofluid of interest, platforms that can robustly handle a large number of samples are essential in the discovery phase of a clinical study.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA, Leiden, The Netherlands. Electronic address:
Cytochrome bd from Mycobacterium tuberculosis (Mtbd) is a menaquinol oxidase that has gained interest as an antibiotic target due to its importance in survival under infectious conditions. Mtbd contains a characteristic disulfide bond that has been hypothesized to allow for Mtbd activity regulation at the enzymatic level, possibly helping M. tuberculosis to rapidly adapt to the hostile environment of the phagosome.
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