Creation of functional protein bioconjugates demands methods for attaching a diverse array of probes to target proteins with high specificity, under mild conditions. The sortase A transpeptidase enzyme from Staphylococcus aureus catalyzes the cleavage of a short 5-aa recognition sequence (LPXTG) with the concomitant formation of an amide linkage between an oligoglycine peptide and the target protein. By functionalizing the oligoglycine peptide, it is possible to incorporate reporters into target proteins in a site-specific fashion. This reaction is applicable to proteins in solution and on the living cell surface. The method described in this unit only requires incubation of the target protein, which has been engineered to contain a sortase recognition site either at the C terminus or within solvent-accessible loops, with a purified sortase enzyme and a suitably functionalized oligoglycine peptide.
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http://dx.doi.org/10.1002/0471140864.ps1503s56 | DOI Listing |
Se Pu
June 2024
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Mitochondria perform various metabolic processes that significantly affect cell differentiation, proliferation, signal transduction, and programmed cell death. The disruption of mitochondrial bioenergetic and metabolic functions is closely related to many disorders. The specific isolation and purification of intact, high-purity, and functional mitochondria are central to the understanding of their mechanism of action but remain challenging tasks.
View Article and Find Full Text PDFMicroorganisms
January 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.
Sortase-mediated ligation (SML) is widely used for protein bioconjugation. However, the sortase used in this strategy typically recognizes only the N-terminal oligoglycine, which is absent in most natural proteins. To broaden the spectrum of substrates compatible with SML, we focus on a novel sortase, sortase A from (SpSrtA), known for its expanded substrate specificity (N-terminal glycine, alanine, and serine).
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
February 2024
Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Collision-induced dissociation (CID) of small, protonated peptides leads to the formation of b-type fragment ions that can occur with several structural motifs driven by different covalent intramolecular bonding arrangements. Here, we characterize the so-called "oxazolone" and "macrocycle" ion structures that occur upon CID of oligoglycine peptides (G) ions ( = 2-6). This is determined by acquiring the vibrational band patterns of the cryogenically cooled, D-tagged ions obtained using isomer-selective, two-color IR-IR photobleaching and analyzing them with predicted (DFT) harmonic spectra for the candidate structures.
View Article and Find Full Text PDFACS Infect Dis
December 2023
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
Among synthetic analogues of antimicrobial peptides (AMPs) under investigation to address antimicrobial resistance, peptoids (-alkylated oligoglycines) have been reported to act both by membrane disruption and on intracellular targets. Here we gradually introduced peptoid units into the membrane-disruptive undecapeptide KKLLKLLKLLL to test a possible transition toward intracellular targeting. We found that selected hybrids containing up to five peptoid units retained the parent AMP's α-helical folding, membrane disruption, and antimicrobial effects against Gram-negative bacteria including multidrug-resistant (MDR) strains of and while showing reduced hemolysis and cell toxicities.
View Article and Find Full Text PDFJ Agric Food Chem
April 2023
School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi 710021, China.
Glycine-rich flexible peptide linkers have been widely adopted in fusion protein engineering; however, they can hardly be cleaved for the separation of fusion partners unless specific protease recognition sites are introduced. Herein, we report the use of the peptidoglycan-targeting staphylolytic enzyme lysostaphin to directly digest the glycine-rich flexible linkers of various lengths including oligoglycine linkers and (GS) linkers, without the incorporation of extra amino acids. Using His-MBP-linker-LbCpf1 as a model substrate, we show that both types of linkers could be digested by lysostaphin, and the digestion efficiency improved with increasing linker length.
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