Structural dynamics of the receptor-binding domain of colicin E9

ABSTRACT The events that occur after the binding of the enzymatic E colicins to Escherichia coli BtuB receptors that lead to translocation of the cytotoxic domain into the periplasmic space and, ultimately, cell killing are poorly understood. It has been suggested that unfolding of the coiled-coil BtuB receptor binding domain of the E colicins may be an essential step that leads to the loss of immunity protein from the colicin and immunity protein complex and then triggers the events of translocation. We introduced pairs of cysteine mutations into the receptor binding domain of colicin E9 (ColE9) that resulted in the formation of a disulfide bond located near the middle or the top of the R domain. After dithiothreitol reduction, the ColE9 protein with the mutations L359C and F412C (ColE9 L359C-F412C) and the ColE9 protein with the mutations Y324C and L447C (ColE9 Y324C-L447C) were slightly less active than equivalent concentrations of ColE9. On oxidation with diamide, no significant biological activity was seen with the ColE9 L359C-F412C and the ColE9 Y324C-L447C mutant proteins; however diamide had no effect on the activity of ColE9. The presence of a disulfide bond was confirmed in both of the oxidized, mutant proteins by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The loss of biological activity of the disulfide-containing mutant proteins was not due to an indirect effect on the properties of the translocation or DNase domains of the mutant colicins. The data are consistent with a requirement for the flexibility of the coiled-coil R domain after binding to BtuB.

Download Full-text

Investigating Early Events in Receptor Binding and Translocation of Colicin E9 Using Synchronized Cell Killing and Proteolytic Cleavage

Journal of Bacteriology ◽

10.1128/jb.00047-08 ◽

2008 ◽

Vol 190 (12) ◽

pp. 4342-4350 ◽

Cited By ~ 14

Author(s):

Ying Zhang ◽

Mireille N. Vankemmelbeke ◽

Lisa E. Holland ◽

David C. Walker ◽

Richard James ◽

...

Keyword(s):

Cell Surface ◽

Receptor Binding ◽

Distal Region ◽

Cell Killing ◽

Binding Domain ◽

Receptor Binding Domain ◽

Cleavage Sites ◽

E Coli ◽

Translocation Domain ◽

Colicin E9

ABSTRACT Enzymatic colicins such as colicin E9 (ColE9) bind to BtuB on the cell surface of Escherichia coli and rapidly recruit a second coreceptor, either OmpF or OmpC, through which the N-terminal natively disordered region (NDR) of their translocation domain gains entry into the cell periplasm and interacts with TolB. Previously, we constructed an inactive disulfide-locked mutant ColE9 (ColE9s-s) that binds to BtuB and can be reduced with dithiothreitol (DTT) to synchronize cell killing. By introducing unique enterokinase (EK) cleavage sites in ColE9s-s, we showed that the first 61 residues of the NDR were inaccessible to cleavage when bound to BtuB, whereas an EK cleavage site inserted at residue 82 of the NDR remained accessible. This suggests that most of the NDR is occluded by OmpF shortly after binding to BtuB, whereas the extreme distal region of the NDR is surface exposed before unfolding of the receptor-binding domain occurs. EK cleavage of unique cleavage sites located in the ordered region of the translocation domain or in the distal region of the receptor-binding domain confirmed that these regions of ColE9 remained accessible at the E. coli cell surface. Lack of EK cleavage of the DNase domain of the cell-bound, oxidized ColE9/Im9 complex, and the rapid detection of Alexa Fluor 594-labeled Im9 (Im9AF) in the cell supernatant following treatment of cells with DTT, suggested that immunity release occurred immediately after unfolding of the colicin and was not driven by binding to BtuB.

Download Full-text

Destabilizing the Structural Integrity of SARS-CoV2 Receptor Proteins by Curcumin Along with Hydroxychloroquine: An Insilco Approach for a Combination Therapy

10.26434/chemrxiv.12090438.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Akhileshwar Srivastava ◽

Divya Singh

Keyword(s):

Binding Energy ◽

Combination Therapy ◽

Receptor Binding ◽

Structural Integrity ◽

Binding Domain ◽

Receptor Binding Domain ◽

Receptor Proteins ◽

Main Protease ◽

The Stability ◽

Therapeutic Activities

Presently, an emerging disease (COVID-19) has been spreading across the world due to coronavirus (SARS-CoV2). For treatment of SARS-CoV2 infection, currently hydroxychloroquine has been suggested by researchers, but it has not been found enough effective against this virus. The present study based on in silico approaches was designed to enhance the therapeutic activities of hydroxychloroquine by using curcumin as an adjunct drug against SARS-CoV2 receptor proteins: main-protease and S1 receptor binding domain (RBD). The webserver (ANCHOR) showed the higher protein stability for both receptors with disordered score (<0.5). The molecular docking analysis revealed that the binding energy (-24.58 kcal/mol) of hydroxychloroquine was higher than curcumin (-20.47 kcal/mol) for receptor main-protease, whereas binding energy of curcumin (<a>-38.84</a> kcal/mol) had greater than hydroxychloroquine<a> (-35.87</a> kcal/mol) in case of S1 receptor binding domain. Therefore, this study suggested that the curcumin could be used as combination therapy along with hydroxychloroquine for disrupting the stability of SARS-CoV2 receptor proteins

Download Full-text

Amoxicillin Trihydrate-Clavulanate Potassium As Potential Inhibitor of 2019 Novel Coronavirus Main Protease with Strong Receptor-Binding Domain (RBD), Molecular Docking and SAR Study

SSRN Electronic Journal ◽

10.2139/ssrn.3580230 ◽

2020 ◽

Author(s):

Khedidja benarous ◽

Talia Serseg ◽

Mohamed Yousfi

Keyword(s):

Molecular Docking ◽

Receptor Binding ◽

Binding Domain ◽

Receptor Binding Domain ◽

Potential Inhibitor ◽

Main Protease ◽

Amoxicillin Trihydrate ◽

Novel Coronavirus ◽

Sar Study

Download Full-text

Amoxicillin and Clavulanate as Potential Multiple Effect Inhibitors of 2019 Novel Coronavirus Main Protease and RNA-Dependent RNA Polymerase with Strong Receptor-Binding Domain (RBD), Molecular Docking and SAR Study

SSRN Electronic Journal ◽

10.2139/ssrn.3618303 ◽

2020 ◽

Author(s):

Khedidja benarous ◽

Talia Serseg ◽

Mohamed Yousfi

Keyword(s):

Molecular Docking ◽

Rna Polymerase ◽

Receptor Binding ◽

Binding Domain ◽

Receptor Binding Domain ◽

Rna Dependent Rna Polymerase ◽

Multiple Effect ◽

Main Protease ◽

Novel Coronavirus ◽

Sar Study

Download Full-text

Role of key point Mutations in Receptor Binding Domain of SARS-CoV-2 Spike Glycoprotein

Infectious Disorders - Drug Targets ◽

10.2174/1871526520666200804161650 ◽

2020 ◽

Vol 20 ◽

Author(s):

Bipin Singh

Keyword(s):

Receptor Binding ◽

Point Mutations ◽

Binding Domain ◽

Receptor Binding Domain ◽

Spike Glycoprotein ◽

Angiotensin Converting Enzyme 2 ◽

Recent Outbreak ◽

Novel Coronavirus ◽

Genomic Similarity

: The recent outbreak of novel coronavirus (SARS-CoV-2 or 2019-nCoV) and its worldwide spread is posing one of the major threats to human health and the world economy. It has been suggested that SARS-CoV-2 is similar to SARSCoV based on the comparison of the genome sequence. Despite the genomic similarity between SARS-CoV-2 and SARSCoV, the spike glycoprotein and receptor binding domain in SARS-CoV-2 shows the considerable difference compared to SARS-CoV, due to the presence of several point mutations. The analysis of receptor binding domain (RBD) from recently published 3D structures of spike glycoprotein of SARS-CoV-2 (Yan, R., et al. (2020); Wrapp, D., et al. (2020); Walls, A. C., et al. (2020)) highlights the contribution of a few key point mutations in RBD of spike glycoprotein and molecular basis of its efficient binding with human angiotensin-converting enzyme 2 (ACE2).

Download Full-text