scholarly journals The Mechanism of NEDD8 Activation of CUL5 Ubiquitin E3 Ligases

2020 ◽  
pp. mcp.RA120.002414
Author(s):  
Ryan J Lumpkin ◽  
Alla S Ahmad ◽  
Rachel Blake ◽  
Christopher J Condon ◽  
Elizabeth A. Komives

Cullin RING E3 Ligases (CRLs) ubiquitylate hundreds of important cellular substrates. Here we have assembled and purified the Ankyrin repeat and SOCS Box protein 9 CUL5 RBX2 Ligase (ASB9-CRL) in vitro and show how it ubiquitylates one of its substrates, CKB. CRLs occasionally collaborate with RING between RING E3 ligases (RBRLs) and indeed, mass spectrometry analysis showed that CKB is specifically ubiquitylated by the ASB9-CRL-ARIH2-UBE2L3 complex. Addition of other E2s such as UBE2R1 or UBE2D2 contribute to polyubiquitylation but do not alter the sites of CKB ubiquitylation. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis revealed that CUL5 neddylation allosterically exposes its ARIH2 binding site, promoting high affinity binding, and it also sequesters the NEDD8 E2 (UBE2F) binding site on RBX2. Once bound, ARIH2 helices near the Ariadne domain active site are exposed, presumably relieving its autoinhibition. These results allow us to propose a model of how neddylation activates ASB-CRLs to ubiquitylate their substrates.

Data in Brief ◽  
2017 ◽  
Vol 15 ◽  
pp. 577-583 ◽  
Author(s):  
Ben K. Ehe ◽  
David R. Lamson ◽  
Michael Tarpley ◽  
Rob U. Onyenwoke ◽  
Lee M. Graves ◽  
...  

Author(s):  
Krishnavignesh L Krishnavignesh ◽  
Mahalakshmipriya A ◽  
Ramesh M

  Objective: Continued resistance toward the antibiotics urges us to explore newer antibiotics. Plants are being the safer source of antibiotics with lesser or no side effects. This study was designed to study the presence of phytochemical constituents and antibacterial activity of leaf and flower extracts of Wedelia glauca against urinary tract infection causing pathogens.Methods: The plant leaves were extracted with five different solvents based on the polarity. The extraction was done using soxhalation. Antimicrobial activity was determined by agar well diffusion method for both the sample and standard. The acetone plant extract was subjected to gas chromatography-mass spectrometry (GC-MS) analysis for screening phytoconstituents.Results: Preliminary phytochemical screening revealed the presence of diverse phytoconstituents in the plant. The different extracts exhibited a considerable antimicrobial potential. Among the solvents used acetone extract showed comparably better antimicrobial activity with 100% of inhibition rate with the maximum zone of inhibition of 1.6±0.77 mm against Staphylococcus sp. and Aspergillus sp. at the concentration of 5 mg. GC-MS analysis provided 8 major peaks which revealed the existence of a variety of bioactive compounds which may attribute to the efficacy of the plant.Conclusion: W. glauca leaf and flower extracts displayed a broad spectrum of antibacterial and antifungal activity and can be considered as a potential source of newer antibiotic compounds.


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