scholarly journals N-terminal truncations on L1 proteins of human papillomaviruses promote their soluble expression in Escherichia coli and self-assembly in vitro

2018 ◽  
Vol 7 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Minxi Wei ◽  
Daning Wang ◽  
Zhihai Li ◽  
Shuo Song ◽  
Xianglin Kong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Self Assembly ◽  
Human Papillomaviruses ◽  
Soluble Expression ◽  
Expression In Escherichia Coli

scholarly journals Large domain movements upon UvrD dimerization and helicase activation

2017 ◽  
Vol 114 (46) ◽  
pp. 12178-12183 ◽  
Author(s):  
Binh Nguyen ◽  
Yerdos Ordabayev ◽  
Joshua E. Sokoloski ◽  
Elizabeth Weiland ◽  
Timothy M. Lohman
Keyword(s):  
Escherichia Coli ◽  
Single Molecule ◽  
Self Assembly ◽  
Total Internal Reflection ◽  
Dna Helicase ◽  
Conformational State ◽  
Helicase Activity ◽  
Multiple Conformations ◽  
Dna Substrate

Escherichia coli UvrD DNA helicase functions in several DNA repair processes. As a monomer, UvrD can translocate rapidly and processively along ssDNA; however, the monomer is a poor helicase. To unwind duplex DNA in vitro, UvrD needs to be activated either by self-assembly to form a dimer or by interaction with an accessory protein. However, the mechanism of activation is not understood. UvrD can exist in multiple conformations associated with the rotational conformational state of its 2B subdomain, and its helicase activity has been correlated with a closed 2B conformation. Using single-molecule total internal reflection fluorescence microscopy, we examined the rotational conformational states of the 2B subdomain of fluorescently labeled UvrD and their rates of interconversion. We find that the 2B subdomain of the UvrD monomer can rotate between an open and closed conformation as well as two highly populated intermediate states. The binding of a DNA substrate shifts the 2B conformation of a labeled UvrD monomer to a more open state that shows no helicase activity. The binding of a second unlabeled UvrD shifts the 2B conformation of the labeled UvrD to a more closed state resulting in activation of helicase activity. Binding of a monomer of the structurally similar Escherichia coli Rep helicase does not elicit this effect. This indicates that the helicase activity of a UvrD dimer is promoted via direct interactions between UvrD subunits that affect the rotational conformational state of its 2B subdomain.

Expression in Escherichia coli and in vitro processing of HIV-1 p24 fusion protein

1993 ◽  
Vol 31 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Ilona Marczinovits ◽  
Imre Boros ◽  
Fouad El Jarrah ◽  
György Füst ◽  
János Molnár
Keyword(s):  
Escherichia Coli ◽  
Fusion Protein ◽  
Expression In Escherichia Coli ◽  
In Vitro Processing ◽  
Hiv 1
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