2799-07-7Relevant articles and documents
Palladium Mediated Rapid Deprotection of N-Terminal Cysteine under Native Chemical Ligation Conditions for the Efficient Preparation of Synthetically Challenging Proteins
Jbara, Muhammad,Maity, Suman Kumar,Seenaiah, Mallikanti,Brik, Ashraf
, p. 5069 - 5075 (2016)
Facilitating the process of chemical protein synthesis is an important goal in order to enable the efficient preparation of large and novel protein analogues. Native chemical ligation, which is widely used in the synthesis and semisynthesis of proteins, has been going through several developments to expedite the synthetic process and to obtain the target protein in high yield. A key aspect of this approach is the utilization of protecting groups for the N-terminal Cys in the middle fragments, which bear simultaneously the two reactive groups, i.e., N-terminal Cys and C-terminal thioester. Despite important progress in this area, as has been demonstrated in the use of thiazolidine protecting group in the synthesis of over 100 proteins, finding optimal protecting group(s) remains a challenge. For example, the thiazolidine removal step is very slow (>8 h), and in some cases the applied conditions lead to undesired side reactions. Here we show that water-soluble palladium(II) complexes are excellent reagents for the effective unmasking of thiazolidine, enabling its complete removal within 15 min under native chemical ligation conditions. Moreover, palladium is also able to rapidly remove propargyloxycarbonyl-protecting group from the N-terminal Cys in a similar efficiency. The utility of the new removal conditions for both protecting groups is exemplified in the rapid and efficient synthesis of Lys34-ubiquitinated H2B and for the first time neddlyated peptides derived from cullin1. The current approach expands the use of palladium in protein chemistry and should significantly facilitate the chemical and semisynthesis of synthetically challenging proteins from multiple fragments.
3-Mercaptopropionic acid-mediated synthesis of peptide and protein thioesters
Kang, Jaskiranjit,Richardson, Jonathan P.,MacMillan, Derek
, p. 407 - 409 (2009)
Peptides and proteins fragment sequence-specifically in the presence of 3-mercaptopropionic acid to afford thioesters which can be used in native chemical ligation reactions. The Royal Society of Chemistry.
Polycysteine as a new type of radio-protector ameliorated tissue injury through inhibiting ferroptosis in mice
Zhang, Junling,Li, Kui,Zhang, Qianru,Zhu, Zhimei,Huang, Gongchao,Tian, Hongqi
, (2021/02/26)
Amifostine has been the only small molecule radio-protector approved by FDA for decades; however, the serious adverse effects limit its clinical use. To address the toxicity issues and maintain the good potency, a series of modified small polycysteine peptides had been prepared. Among them, compound 5 exhibited the highest radio-protective efficacy, the same as amifostine, but much better safety profile. To confirm the correlation between the radiation-protective efficacy and the DNA binding capability, each of the enantiomers of the polycysteine peptides had been prepared. As a result, the l-configuration compounds had obviously higher efficacy than the corresponding d-configuration enantiomers; among them, compound 5 showed the highest DNA binding capability and radiation-protective efficacy. To our knowledge, this is the first study that has proved their correlations using direct comparison. Further exploration of the mechanism revealed that the ionizing radiation (IR) triggered ferroptosis inhibition by compound 5 could be one of the pathways for the protection effect, which was different from amifostine. In summary, the preliminary result showed that compound 5, a polycysteine as a new type of radio-protector, had been developed with good efficacy and safety profile. Further study of the compound for potential use is ongoing.
Convergent Total Synthesis of the Siderophore Piscibactin as Its Ga3+Complex
De La Fuente, M. Carmen,Jiménez, Carlos,Rodríguez, Jaime,Segade, Yuri,Valderrama, Katherine
supporting information, p. 340 - 345 (2021/01/13)
The siderophore piscibactin is a key virulence factor involved in the iron uptake of pathogenic bacteria Photobacterium damselae subsp. piscicida and Vibrio anguillarum, responsible for the fish diseases photobacterioisis (pasteurellosis) and vibriosis, respectively. A convergent total synthesis of its Ga3+ complex using l-/d-cysteine as chiral agents and Meldrum's acid is described. A Staudinger reduction/Aza-Wittig process in the synthesis of the acid-sensitive β-hydroxy-2,4-disubstituted thiazoline moiety and the convenient protecting groups was a key step in this synthesis.