LAB peptides ([..], CPC Scientific, [..] l, standard solid-phase peptide synthesis) at 10 mM in 50 mM Tris, pH 8, and 100 mM NaCl were diluted in MHB II cation adjusted broth (800 μM top concentration) or LB. Where indicated, EDTA was added to a final concentration of 0.5 mM.
Abstract
Lipopolysaccharide (LPS) resides in the outer membrane of Gram-negative bacteria where it is responsible for barrier function. LPS can cause death as a result of septic shock, and its lipid A core is the target of polymyxin antibiotics. Despite the clinical importance of polymyxins and the emergence of multidrug resistant strains5, our understanding of the bacterial factors that regulate LPS biogenesis is incomplete. Here we characterize the inner membrane protein PbgA and report that its depletion attenuates the virulence of Escherichia coli by reducing levels of LPS and outer membrane integrity. In contrast to previous claims that PbgA functions as a cardiolipin transporter, our structural analyses and physiological studies identify a lipid A-binding motif along the periplasmic leaflet of the inner membrane. Synthetic PbgA-derived peptides selectively bind to LPS in vitro and inhibit the growth of diverse Gram-negative bacteria, including polymyxin-resistant strains. Proteomic, genetic and pharmacological experiments uncover a model in which direct periplasmic sensing of LPS by PbgA coordinates the biosynthesis of lipid A by regulating the stability of LpxC, a key cytoplasmic biosynthetic enzyme. In summary, we find that PbgA has an unexpected but essential role in the regulation of LPS biogenesis, presents a new structural basis for the selective recognition of lipids, and provides opportunities for future antibiotic discovery.
SOCIAL MEDIA
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Development of a selective, sensitive and robust oxyntomodulin dual monoclonal antibody immunoassay.
Umberger, T.S., Ming, W., Cox, J.M., Konrad, R.J. and Siegel, R.W. Bioanalysis 14, no. 18 (2022): 1229-1239.
- Lilly Research Laboratories, Eli Lilly & Company, Indianapolis, IN46285, USA
Human K2 EDTA and P800 plasma (500 μl) was spiked with proglucagon 33–61, 35–61 and 36–61 stable-isotope-labeled internal standard peptides (CPC Scientific, custom order) and diluted with I buffer (25 mmol/l Tris-HCl, 25 mmol/l HEPES, 300 mmol/l NaCl, 0.1% (v/v) octyl β-D-glucopyranoside, pH 7.5).
Line, J.E.; Seal, B.S.; Garrish, J.K. Appl. Microbiol. 2022, 2, 688–700.
Peptides were synthesized using standard solid-phase(Fmoc) chemistry with a peptide synthesizer (CPC Scientific Inc., Sunnyvale, CA 94089,USA, C12K-2β12 [..]
Kirk, N.S., Chen, Q., Wu, Y.G., Asante, A.L., Hu, H., Espinosa, J.F., Martínez-Olid, F., Margetts, M.B., Mohammed, F.A., Kiselyov, V.V. and Barrett, D.G. Nature Communications 13, no. 1 (2022): 5695.
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
Peptides were synthesized under contract by CPC Scientific, except for the N-terminally acetylated version of IM172N22 and the Glu3Arg, Glu3Ala, Glu4Arg, Glu4Ala, Glu5Ala, Glu5Arg, Trp6Ala, Gln8Ala, Ile9Ala, Glu10Ala, Glu10Arg and Tyr14Ala mutants of IM172N22
Coskun, T., Urva, S., Roell, W.C., Qu, H., Loghin, C., Moyers, J.S., O’Farrell, L.S., Briere, D.A., Sloop, K.W., Thomas, M.K. and Pirro, V. Cell Metabolism 34, no. 9 (2022): 1234-1247.
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA
Homologous and heterologous competition experiments were performed with non-radioactive peptide analogues[127I]-Tyr1-GIP(1-42) and [127]-Tyr10-GIP(1-42) to ensure quantification of the high-affinity binding site of the GIPR. Peptide analogues were generated using synthetic [127I]-Tyr amino acid building blocks (CPC Scientific).
Cecil, D.L., Curtis, B., Gad, E., Gormley, M., Timms, A.E., Corulli, L., Bos, R., Damle, R.N., Sepulveda, M.A. and Disis, M.L. Scientific Reports 12, no. 1 (2022): 13618.
- Cancer Vaccine Institute, University of Washington, 850 Republican Street, Brotman Bld., 2nd Floor, Box 358050, Seattle, WA 98195-8050, USA.
- Janssen Research and Development LLC, Spring House, PA, USA.
- Janssen Vaccines and Prevention, Leiden, The Netherlands.
The peptides were constructed and purified by high-performance liquid chromatography (> 90% pure; CPC Scientific).
Zonari, A., Brace, L.E., Alencar-Silva, T., Porto, W.F., Foyt, D., Guiang, M., Cruz, E.A.O., Franco, O.L., Oliveira, C.R., Boroni, M. and Carvalho, J.L. Toxicology Reports 9 (2022): 1632-1638.
Peptide 14 (ETAKHWLKGI) (Sup. Fig. 1) was purchased from CPC Scientific Inc. (USA), which synthesized the peptide by solid phase (Fmoc) on a Rink amide resin, with > 95% purity, in the form of acetate salt.
CPC Scientific Inc., a leading global peptide CRDMO (Contract Research, Development, and Manufacturing Organization) has invested in a new peptide API (Active Pharmaceutical Ingredient) manufacturing site, bringing many new jobs to Rocklin, California. The 41,000 sq ft facility located at 3880 Atherton Rd, Rocklin, CA 95765 will be utilized to manufacture clinical to commercial grade peptide products for increased manufacturing capacity and will diversify CPC Scientific’s supply chain.
CPC Scientific is entering an exciting period of growth and innovation for peptide and oligonucleotide therapeutic development and manufacturing, and we will continue to provide therapeutic APIs to pharmaceutical and biotech companies around the world. We are very pleased to partner with the City of Rocklin, California to bring manufacturing and Life-Science jobs to local American workers,” said Shawn Lee, PhD, CEO.
Ikeda, Z., Kakegawa, K., Kikuchi, F., Itono, S., Oki, H., Yashiro, H., Hiyoshi, H., Tsuchimori, K., Hamagami, K., Watanabe, M. and Sasaki, M. Journal of Medicinal Chemistry 65, no. 12 (2022): 8456-8477.
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
Subsequently, 5FAM–Abu–Gly–Asp–Asp–Asp–Lys–Ile–Val–Gly–Gly–Lys(CPQ2)–Lys–Lys–NH2 (purity: 97.2%, CPC Scientific, Inc.) was diluted with an assay buffer to prepare a 2.1 μM substrate solution.
The transferred energy from a fluorescent donor is converted into molecular vibrations if the acceptor is a non-fluorescent dye (quencher). When the FRET is terminated (by separating donor and acceptor), an increase of donor fluorescence can be detected. The design and synthesis work at CPC for FRET and TR-FRET peptide substrates include modification of sequences, selection of donor/quencher pairs, improvement of FRET substrate solubility and quenching efficiency.