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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Clpxp Degradation System In Escherichia Coli, A Study Of Its Energy Sources And Its Applications In Managing The Expression Levels Of Targeted Membrane And Soluble Proteins, Thilini Abeywansha
Clpxp Degradation System In Escherichia Coli, A Study Of Its Energy Sources And Its Applications In Managing The Expression Levels Of Targeted Membrane And Soluble Proteins, Thilini Abeywansha
Theses and Dissertations--Chemistry
ClpXP is an Escherichia coli protease that carries out energy-dependent intracellular proteolysis. In recent years, this system has been widely studied due to its importance as protein regulatory machinery and a virulence factor. Protein substrates of ClpXP contain degrons with a specific protein sequence. SsrA tag is one of the five degrons known to designate proteins for ClpXP degradation. SsrA is an 11 amino acid peptide added to the C-terminus of nascent polypeptide chains translated from aberrant messenger RNAs lacking stop codons via a process called trans-translation.
ClpXP was known to targets only cytosolic proteins with degrons until recently, …
Investigation Of Multidrug Efflux Transporter Acrb In Escherichia Coli: Assembly, Degradation And Dynamics, Prasangi Irosha Rajapaksha
Investigation Of Multidrug Efflux Transporter Acrb In Escherichia Coli: Assembly, Degradation And Dynamics, Prasangi Irosha Rajapaksha
Theses and Dissertations--Chemistry
The Resistant Nodulation Division (RND) super family member, tripartite AcrA-AcrB-TolC efflux pump, is a major contributor in conferring multidrug-resistance in Escherichia coli. The structure of the pump complex, and drug translocation by functional rotation mechanism have been widely studied. Despite of all these data, the dynamics of the assembly process of the pump and AcrB during functional rotation in the process of drug efflux remains poorly understood. My thesis focuses on understanding the pump assembly process, dynamics of AcrB in functional rotation mechanism, and also investigate the mechanism of degradation of AcrB facilitated by a C-terminal ssrA tag.
In the …
Illuminate The Pathway Of Membrane Protein Association And Degradation, Zhaoshuai Wang
Illuminate The Pathway Of Membrane Protein Association And Degradation, Zhaoshuai Wang
Theses and Dissertations--Chemistry
Escherichia coli transporter protein AcrB and its homologues are the inner membrane components of the Resistance-Nodulation-Division (RND) family efflux pumps in Gram-negative bacteria. It is well accepted that soluble proteins are only marginally stable, but such insight is missing for membrane proteins. The lack of stability data, including thermodynamic stability and oligomer association affinity is a result of intrinsic difficulties in working with membrane proteins. In addition, the degradation of soluble proteins in E. coli has been extensively studied whereas the degradation process of membrane proteins remains unclear. A focus of my thesis is the validation and development of methods …
Assembly And Degradation Of A Trimeric Membrane Protein Acrb, Qian Chai
Assembly And Degradation Of A Trimeric Membrane Protein Acrb, Qian Chai
Theses and Dissertations--Chemistry
Multidrug efflux pumps are membrane proteins that actively transport foreign objects out of cells. The active efflux of these pumps is a critical self-defense mechanism that enables the survival of bacteria under hostile environments. Efflux pump AcrB is a member of the Resistance-Nodulation-Division (RND) super family. In E. coli, it associates with periplasmic protein AcrA and outer membrane channel TolC to extrude a variety of noxious compounds out of cell from both the cytoplasm and the periplasm. My dissertation research focused on two aspects of this multidrug efflux pump: the oligomerization process during the biogenesis of AcrB and its …
Stability Studies Of Membrane Proteins, Cui Ye
Stability Studies Of Membrane Proteins, Cui Ye
Theses and Dissertations--Chemistry
The World Health Organization has identified antimicrobial resistance as one of the top three threats to human health. Gram-negative bacteria such as Escherichia coli are intrinsically more resistant to antimicrobials. There are very few drugs either on the market or in the pharmaceutical pipeline targeting Gram-negative pathogens. Two mechanisms, the protection of the outer membrane and the active efflux by the multidrug transporters, play important roles in conferring multidrug resistance to Gram-negative bacteria. My work focuses on two main directions, each aligning with one of the known multidrug resistance mechanisms.
The first direction of my research is in the area …
Understanding Multidrug Resistance In Gram-Negative Bacteria -- A Study Of A Drug Efflux Pump Acrb And A Periplasmic Chaperone Sura, Meng Zhong
Theses and Dissertations--Chemistry
Multiple drug resistance (MDR) has been a severe issue in treatment and recovery from infection.Gram-negative bacteria intrinsically exhibit higher drug tolerance than Gram-positive microbes. In this thesis, two proteins involved in Gram-negative bacterial MDR were studied, AcrB and SurA.
Resistance-nodulation-cell division pump AcrAB-TolC is the major MDR efflux system in Gram-negative bacteria and efficiently extrudes a broad range of substances from the cells. To study subtle conformational changes of AcrB in vivo, a reporter platform was designed. Cysteine pairs were introduced into different regions in the periplasmic domain of the protein, and the extents of disulfide bond formation were …