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According to classical immunology theory, immunoglobulin (Ig) is exclusively produced by differentiated B lymphocytes, which exhibit a typical tetrapeptide chain structure and are predominantly present on the surface of B cells and in bodily fluids. B-Ig is one of the critical effector molecules for humoral immune responses specifically recognising antigens and eliminating them. However, mounting evidence has demonstrated that Ig is widely expressed in non B lineage cells, especially malignant ones (referred to as non B-Ig). Interestingly, non B-Ig mainly resides in the cytoplasm and secretion, but to some extent on the cell surface. Furthermore non B-Ig not only displays a tetrapeptide chain structure but also shows free heavy chains and free light chains (FLCs). Additionally, Ig derived from non B cancer cell typically displays unique glycosylation modifications. Functionally, non B-Ig demonstrated diversity and versatility, showing antibody activity and cellular biological activity, such as promoting cell proliferation and survival, and it is implicated in cancer progression and some immune-related diseases, such as renal diseases.
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http://dx.doi.org/10.1007/978-981-97-0511-5_5 | DOI Listing |
J Am Soc Mass Spectrom
August 2025
National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India.
Mass spectral fragmentation of the tripeptide amide Ala-Lys-Ala-amide (AKA*) yields a product ion at / 228.1, which corresponds to a neutral loss of 43 Da from the ion (/ 271.1).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, 66045, USA.
Dehydroamino acids (ΔAAs) are vital building blocks in the design and optimization of peptide drugs. The exact olefin geometry, side chain chemotype, and ancillary β-carbon substituents play a significant role. Unfortunately, general approaches to install these motifs into peptides are lacking, complicated by the instability of unsaturated residues during traditional amide-bond coupling and failure of divergent protocols, such as oxidative Heck and Horner-Wadsworth-Emmons, to accommodate a complete range of substrate classes.
View Article and Find Full Text PDFChem Sci
August 2025
Institute for Molecular Bio Science, Goethe University Frankfurt Max-von-Laue Strasse 9 60438 Frankfurt am Main Germany
Cyclic peptides exhibit diverse bioactivities and are distinguished by their enhanced cell permeability, improved proteolytic stability, and increased binding affinity due to their conformational rigidity. Despite significant advancements in peptide synthesis, the production of complex cyclic peptides remains a challenge. Nature has evolved diverse strategies for peptide cyclization, with an ever-growing repertoire of characterized cyclases involved in the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs).
View Article and Find Full Text PDFACS Omega
July 2025
Research Center for Autonomous Systems Materialogy (ASMat), Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
Metal coordination has emerged as a promising strategy to modulate peptide self-assembly and enhance crystal stability. In this study, we investigated the crystallization behavior of a histidine-containing tetrapeptide in the presence and absence of copper ions to elucidate the role of metal coordination in peptide assembly. Crystals were obtained under both conditions and characterized using single-crystal X-ray diffraction (sc-XRD) and angle-resolved polarized Raman spectroscopy.
View Article and Find Full Text PDFBMC Chem
July 2025
School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China.
Analogues of chlamydocin derivatives consistently demonstrate multifaceted bioactivities, particularly through HDAC inhibition mechanisms, oncolytic efficacy, and neuronal preservation capacities. These activities primarily originate from their unique cyclic tetrapeptide scaffold and functional groups within the side chains that enable specific interactions with biomacromolecules. We herein report the total syntheses of three naturally occurring chlamydocin analogues-koshidacin B, TAN-1746, and Ac-TAN-1746.
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