The outcome of the Michael-type reaction between thiols and 2,2-disubstituted cyclopentenediones varies depending on the thiol. Stable compounds with two fused rings were formed upon reaction with 1,2-aminothiols (such as N-terminal cysteines in peptides). Other thiols gave reversibly Michael-type adducts that were in equilibrium with the starting materials. This differential reactivity allows differently placed cysteines to be distinguished and has been exploited to prepare bioconjugates incorporating two or three different moieties.
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http://dx.doi.org/10.1021/acs.orglett.6b02301 | DOI Listing |
EMBO J
January 2025
Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA.
The complement system and neutrophils constitute the two main pillars of the host innate immune defense against infection by bacterial pathogens. Here, we identify T-Mac, a novel virulence factor of the periodontal pathogen Treponema denticola that allows bacteria to evade both defense systems. We show that T-Mac is expressed as a pre-protein that is cleaved into two functional units.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Biochemistry and Biophysics, Texas A&M University, 301 Old Main Drive, College Station, Texas 77845, United States.
SARS-CoV-2 3CL protease (Main protease) and human cathepsin L are proteases that play unique roles in the infection of human cells by SARS-CoV-2, the causative agent of COVID-19. Both proteases recognize leucine and other hydrophobic amino acids at the P position of a peptidomimetic inhibitor. At the P position, cathepsin L accepts many amino acid side chains, with a partial preference for phenylalanine, while 3CL-PR protease has a stringent specificity for glutamine or glutamine analogues.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
Pulsed dipolar electron paramagnetic resonance (PD-EPR) measurement is a powerful technique for characterizing the interactions and conformational changes of biomolecules. The extraction of these distance restraints from PD-EPR experiments relies on manipulation of spin-spin pairs. The orthogonal spin labeling approach offers unique advantages by providing multiple distances between different spin-spin pairs.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
December 2024
State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China.
Nonstructural protein 3C, a master protease of Picornaviridae, plays a critical role in viral replication by directly cleaving the viral precursor polyprotein to form the viral capsid protein and antagonizing the host antiviral response. Additionally, 3C protease, as a tool enzyme, is involved in regulating polyprotein expression. Here, the 3C mutant gene (3Cm), fused with a small ubiquitin-like modifier (SUMO) tag at the N-terminal and featuring a mutation at position 127, was inserted into the cold-shock plasmid pCold of Escherichia coli for expression.
View Article and Find Full Text PDFCommun Biol
December 2024
College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China.
Encapsulin nanocompartments loaded with dedicated cargo proteins via unique targeting peptides, play a key role in stress resistance, iron storage and natural product biosynthesis. Mmp1 and cysteine desulfurase (Enc-CD) have been identified as the most abundant representatives of family 2 encapsulin systems. However, the molecular assembly, catalytic mechanism, and physiological functions of the Mmp1 encapsulin system have not been studied in detail.
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