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1. Fast Cysteine Bioconjugation Chemistry

   https://doi.org/10.1002/chem.202201843  

   Chen, Fa‐Jie; Gao, Jianmin (September 2022, Chemistry – A European Journal)

   Abstract Cysteine bioconjugation serves as a powerful tool in biological research and has been widely used for chemical modification of proteins, constructing antibody‐drug conjugates, and enabling cell imaging studies. Cysteine conjugation reactions with fast kinetics and exquisite selectivity have been under heavy pursuit as they would allow clean protein modification with just stoichiometric amounts of reagents, which minimizes side reactions, simplifies purification and broadens functional group tolerance. In this concept, we summarize the recent advances in fast cysteine bioconjugation, and discuss the mechanism and chemical principles that underlie the high efficiencies of the newly developed cysteine reactive reagents. 

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2. Ultra-rapid Electrophilic Cysteine Arylation

   https://doi.org/10.1021/jacs.3c10334  

   Lipka, Bradley M.; Honeycutt, Daniel S.; Bassett, Gregory M.; Kowal, Taylor N.; Adamczyk, Max; Cartnick, Zachary C.; Betti, Vincent M.; Goldberg, Jacob M.; Wang, Fang (November 2023, Journal of the American Chemical Society)
3. Methods to Investigate the Kinetic Profile of Cysteine Desulfurases

   https://doi.org/https://doi.org/10.1007/978-1-0716-1605-5_10  

   Addo, M.A.; Edwards, A. E.; Dos Santos, P.C. (July 2021, Methods in molecular biology)

   Dos Santos, P.C. (Ed.)

   Biological iron-sulfur (Fe-S) clusters are essential protein prosthetic groups that promote a range of biochemical reactions. In vivo, these clusters are synthesized by specialized protein machineries involved in sulfur mobilization, cluster assembly, and cluster transfer to their target proteins. Cysteine desulfurases initiate the first step of sulfur activation and mobilization in cluster biosynthetic pathways. The reaction catalyzed by these enzymes involves the abstraction of sulfur from the amino acid l-cysteine, with concomitant formation of alanine. The presence and availability of a sulfur acceptor modulate the sulfurtransferase activity of this class of enzymes by altering their reaction profile and catalytic turnover rate. Herein, we describe two methods used to probe the reaction profile of cysteine desulfurases through quantification of alanine and sulfide production in these reactions. 

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4. Impact of an alpha helix and a cysteine–cysteine disulfide bond on the resistance of bacterial adhesion pili to stress

   https://doi.org/10.1073/pnas.2023595118  

   Baker, Joseph L.; Dahlberg, Tobias; Bullitt, Esther; Andersson, Magnus (May 2021, Proceedings of the National Academy of Sciences)

   Escherichia coliexpress adhesion pili that mediate attachment to host cell surfaces and are exposed to body fluids in the urinary and gastrointestinal tracts. Pilin subunits are organized into helical polymers, with a tip adhesin for specific host binding. Pili can elastically unwind when exposed to fluid flow forces, reducing the adhesin load, thereby facilitating sustained attachment. Here we investigate biophysical and structural differences of pili commonly expressed on bacteria that inhabit the urinary and intestinal tracts. Optical tweezers measurements reveal that class 1a pili of uropathogenicE. coli(UPEC), as well as class 1b of enterotoxigenicE. coli(ETEC), undergo an additional conformational change beyond pilus unwinding, providing significantly more elasticity to their structure than ETEC class 5 pili. Examining structural and steered molecular dynamics simulation data, we find that this difference in class 1 pili subunit behavior originates from an α-helical motif that can unfold when exposed to force. A disulfide bond cross-linking β-strands in class 1 pili stabilizes subunits, allowing them to tolerate higher forces than class 5 pili that lack this covalent bond. We suggest that these extra contributions to pilus resiliency are relevant for the UPEC niche, since resident bacteria are exposed to stronger, more transient drag forces compared to those experienced by ETEC bacteria in the mucosa of the intestinal tract. Interestingly, class 1b ETEC pili include the same structural features seen in UPEC pili, while requiring lower unwinding forces that are more similar to those of class 5 ETEC pili. 

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5. Structural basis for tRNA-dependent cysteine biosynthesis

   https://doi.org/10.1038/s41467-017-01543-y  

   Chen, Meirong; Kato, Koji; Kubo, Yume; Tanaka, Yoshikazu; Liu, Yuchen; Long, Feng; Whitman, William B.; Lill, Pascal; Gatsogiannis, Christos; Raunser, Stefan; et al (December 2017, Nature Communications)