233266-69-8Relevant articles and documents
Expanding the scope of N → S acyl transfer in native peptide sequences
Cowper, Ben,Shariff, Leila,Chen, Wenjie,Gibson, Samantha M.,Di, Wei-Li,Macmillan, Derek
, p. 7469 - 7476 (2015)
Understanding the factors that influence N → S acyl transfer in native peptide sequences, and discovery of new reagents that facilitate it, will be key to expanding its scope and applicability. Here, through a study of short model peptides in thioester formation and cyclisation reactions, we demonstrate that a wider variety of Xaa-Cys motifs than originally envisaged are capable of undergoing efficient N → S acyl transfer. We present data for the relative rates of thioester formation and cyclisation for a representative set of amino acids, and show how this expanded scope can be applied to the production of the natural protease inhibitor Sunflower Trypsin Inhibitor-1 (SFTI-1).
Protein ubiquitination: Via dehydroalanine: Development and insights into the diastereoselective 1,4-addition step
Meledin, Roman,Mali, Sachitanand M.,Singh, Sumeet K.,Brik, Ashraf
, p. 4817 - 4823 (2016)
We report a strategy for site-specific protein ubiquitination using dehydroalanine (Dha) chemistry for the preparation of ubiquitin conjugates bearing a very close mimic of the native isopeptide bond. Our approach relies on the selective formation of Dha followed by conjugation with hexapeptide bearing a thiol handle derived from the C-terminal of ubiquitin. Subsequently, the resulting synthetic intermediate undergoes native chemical ligation with the complementary part of the ubiquitin polypeptide. It has been proposed that the Michael addition step could result in the formation of a diastereomeric mixture as a result of unselective protonation of the enolate intermediate. It has also been proposed that the chiral protein environment may influence such an addition step. In the protein context these questions remain open and no experimental evidence was provided as to how such a protein environment affects the diastereoselectivity of the addition step. As was previously proposed for the conjugation step on protein bearing Dha, the isopeptide bond formation step in our study resulted in the construction of two protein diastereomers. To assign the ratio of these diastereomers, trypsinization coupled with high-pressure liquid chromatography analysis were performed. Moreover, the obtained peptide diastereomers were compared with identical synthetic peptides having defined stereogenic centers, which enabled the determination of the configuration of the isopeptide mimic in each diastereomer. Our study, which offers a new method for isopeptide bond formation and protein ubiquitination, gives insights into the parameters that affect the stereoselectivity of the addition step to Dha for chemical protein modifications.
Visible-Light-Mediated S?H Bond Insertion Reactions of Diazoalkanes with Cysteine Residues in Batch and Flow
Chen, Lin,Cui, Yu-Sheng,Duan, Xiu,Guo, Kai,Qin, Long-Zhou,Qiu, Jiang-Kai,Sun, Qi,Yuan, Xin,Zhuang, Kai-Qiang
, p. 5093 - 5104 (2020/09/23)
We describe the application of S?H bond insertion reactions of aryl diazoacetates with cysteine residues that enabled metal-free, S?H functionalization under visible-light conditions. Moreover, this process could be intensified by a continuous-flow photomicroreactor on the acceleration of the reaction (6.5 min residence time). The batch and flow protocols described were applied to obtain a wide range of functionalized cysteine derivatives and cysteine-containing dipeptides, thus providing a straightforward and general platform for their functionalizations in mild conditions. (Figure presented.).
Synthesis and NMR Characterization of the Prenylated Peptide, a-Factor
Bader, Taysir K.,Rappe, Todd M.,Veglia, Gianlugi,Distefano, Mark D.
, p. 207 - 238 (2019/01/04)
Protein and peptide prenylation is an essential biological process involved in many signal transduction pathways. Hence, it plays a critical role in establishing many major human ailments, including Alzheimer's disease, amyotrophic lateral sclerosis (ALS), malaria, and Ras-related cancers. Yeast mating pheromone a-factor is a small dodecameric peptide that undergoes prenylation and subsequent processing in a manner identical to larger proteins. Due to its small size in addition to its well-characterized behavior in yeast, a-factor is an attractive model system to study the prenylation pathway. Traditionally, chemical synthesis and characterization of a-factor have been challenging, which has limited its use in prenylation studies. In this chapter, a robust method for the synthesis of a-factor is presented along with a description of the characterization of the peptide using MALDI and NMR. Finally, complete assignments of resonances from the isoprenoid moiety and a-factor from COSY, TOCSY, HSQC, and long-range HMBC NMR spectra are presented. This methodology should be useful for the synthesis and characterization of other mature prenylated peptides and proteins.
