Bacteriophage T7 RNA polymerase was covalently modified by 5'-[4-fluorosulfonyl)benzoyl]adenosine (4-FSO2BzAdo). The modified enzyme lacks the ability to catalyze RNA synthesis from the phi 10 promoter of bacteriophage T7; both promoter and GTP binding being markedly decreased. The mild hydrolysis of the ester bond of 4-FSO2BzAdo within the covalent enzyme-inhibitor complex restores the RNA synthesis at a lower rate. Sequence studies show that Lys172 is the target of modification by 4-FSO2BzAdo. This residue, which is situated in the polypeptide region connecting two domains of RNA polymerase, was shown to be the primary site of the limited proteolysis occurring in vivo [Ikeda, R. A. & Richardson, C. C. (1987) J. Biol. Chem. 262, 3790-3799]. We propose that Lys172 is located outside the active site. Once this residue has reacted with 4-FSO2BzAdo, the nucleoside moiety of the analog is fixed in the NTP-binding site of the active centre and prevents binding of the substrates. Here, Lys172 per se is not important for the activity but serves as an 'anchor' for binding of the inhibitor.
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http://dx.doi.org/10.1111/j.1432-1033.1990.tb19098.x | DOI Listing |
Sci Adv
January 2025
Department of Hematology, Zhongda Hospital, Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China.
SPT5 exhibits versatile functions in RNA Pol II promoter proximal pausing, pause release, and elongation in metazoans. However, the mechanism underlying the functional switch of SPT5 during early elongation has not been fully understood. Here, we report that the phosphorylation site-rich domain (PRD)/CTR1 and the prion-like domain (PLD)/CTR2, which are situated adjacent to each other within the C-terminal repeat (CTR) in SPT5, play pivotal roles in Pol II pausing and elongation, respectively.
View Article and Find Full Text PDFCell Rep
January 2025
Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China; NHC Key Laboratory of Birth Defect Prevention, Zhengzhou, Henan 451163, P.R. China. Electronic address:
Quantification of transcription activities in mammalian preimplantation embryos is challenging due to a huge amount of maternally stored transcripts and paucity of research materials. Here, we investigate genome-wide transcription activities of mouse and human preimplantation embryos by quantifying elongating RNA polymerase II. Two transcriptional waves are identified in early mouse embryos, with summits at the 2-cell and 8-cell stages.
View Article and Find Full Text PDFTransl Pediatr
December 2024
Department of Gynecology, Hangzhou Children's Hospital, Hangzhou, China.
Background: () is associated with a variety of malignancies. However, the role of in osteosarcoma and its underlying mechanism are not yet fully understood. This study aimed to explore the role and the mechanism of in osteosarcoma.
View Article and Find Full Text PDFTransl Pediatr
December 2024
Department of Infectious Diseases, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Background: Chronic active Epstein-Barr virus (CAEBV) infection is a rare disease in which the Epstein-Barr virus (EBV) persists and replicates, causing chronic symptoms and fatal complications. The treatment of CAEBV is still evolving. Our case report showed a new therapy for CAEBV.
View Article and Find Full Text PDFGlycoconj J
January 2025
School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
Chondroitin sulphate (CS) is a sulphated glycosaminoglycan (GAG) polysaccharide found on proteoglycans (CSPGs) in extracellular and pericellular matrices. Chondroitinase ABC (CSase ABC) derived from Proteus vulgaris is an enzyme that has gained attention for the capacity to cleave chondroitin sulphate (CS) glycosaminoglycans (GAG) from various proteoglycans such as Aggrecan, Neurocan, Decorin etc. The substrate specificity of CSase ABC is well-known for targeting various structural motifs of CS chains and has gained popularity in the field of neuro-regeneration by selective degradation of CS GAG chains.
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