Kinetics of Protein Modification Reactions: Analysis of Modification-Induced Protein Unfolding

1987 ◽  
Vol 1 (4) ◽  
pp. 289-299 ◽  
Author(s):  
Emmanuel T. Rakitzis
Keyword(s):  
Protein Modification ◽  
Protein Unfolding ◽  
Kinetics Of

scholarly journals A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism

2019 ◽  
Vol 116 (38) ◽  
pp. 18822-18826 ◽  
Author(s):  
Runze Li ◽  
Dinesh Dhankhar ◽  
Jie Chen ◽  
Thomas C. Cesario ◽  
Peter M. Rentzepis
Keyword(s):  
Fluorescence Intensity ◽  
Protein Unfolding ◽  
Uv Light ◽  
Quantum Yields ◽  
Continuous Irradiation ◽  
Minute Period ◽  
Bacteria Inactivation ◽  
Tryptophan Residues ◽  
Inactivation Mechanism ◽  
Kinetics Of

The UV photodissociation kinetics of tryptophan amino acid, Trp, attached to the membrane of bacteria, Escherichia coli and Bacillus subtilis, have been studied by means of normal and synchronous fluorescence. Our experimental data suggest that the fluorescence intensity of Trp increases during the first minute of irradiation with 250 nm to ∼ 280 nm, 7 mW/cm2 UV light, and subsequently decreases with continuous irradiation. During this short, less than a minute, period of time, 70% of the 107 cell per milliliter bacteria are inactivated. This increase in fluorescence intensity is not observed when tryptophan is in the free state, namely, not attached to a protein, but dissolved in water or saline solution. This increase in fluorescence is attributed to the additional fluorescence of tryptophan molecules formed by protein unfolding, the breakage of the bond that attaches Trp to the bacterial protein membrane, or possibly caused by the irradiation of 2 types of tryptophan residues that photolyze with different quantum yields.

Kinetics of breaking a salt-bridge critical in protein unfolding

2004 ◽  
Vol 385 (5-6) ◽  
pp. 337-340 ◽  
Author(s):  
Andreea D. Gruia ◽  
Stefan Fischer ◽  
Jeremy C. Smith
Keyword(s):  
Protein Unfolding ◽  
Salt Bridge ◽  
Kinetics Of

scholarly journals Kinetics of protein modification reactions

1984 ◽  
Vol 217 (2) ◽  
pp. 341-351 ◽  
Author(s):  
E T Rakitzis
Keyword(s):  
Protein Modification ◽  
Kinetics Of

scholarly journals Assaying the kinetics of protein denaturation catalyzed by AAA+ unfolding machines and proteases

2015 ◽  
Vol 112 (17) ◽  
pp. 5377-5382 ◽  
Author(s):  
Vladimir Baytshtok ◽  
Tania A. Baker ◽  
Robert T. Sauer
Keyword(s):  
Protein Unfolding ◽  
Protein Denaturation ◽  
Molecular Machines ◽  
The Self ◽  
The Other ◽  
Robust Methods ◽  
Specific Proteins ◽  
Dimeric Subunit ◽  
Kinetics Of

ATP-dependent molecular machines of the AAA+ superfamily unfold or remodel proteins in all cells. For example, AAA+ ClpX and ClpA hexamers collaborate with the self-compartmentalized ClpP peptidase to unfold and degrade specific proteins in bacteria and some eukaryotic organelles. Although degradation assays are straightforward, robust methods to assay the kinetics of enzyme-catalyzed protein unfolding in the absence of proteolysis have been lacking. Here, we describe a FRET-based assay in which enzymatic unfolding converts a mixture of donor-labeled and acceptor-labeled homodimers into heterodimers. In this assay, ClpX is a more efficient protein-unfolding machine than ClpA both kinetically and in terms of ATP consumed. However, ClpP enhances the mechanical activities of ClpA substantially, and ClpAP degrades the dimeric substrate faster than ClpXP. When ClpXP or ClpAP engage the dimeric subunit, one subunit is actively unfolded and degraded, whereas the other subunit is passively unfolded by loss of its partner and released. This assay should be broadly applicable for studying the mechanisms of AAA+ proteases and remodeling chaperones.

Sign in / Sign up

Export Citation Format

Share Document