Isolation of Peptide Ligands that Inhibit Glutamate Racemase Activity from a Random Phage Display Library

2000 ◽  
Vol 5 (6) ◽  
pp. 435-440 ◽  
Author(s):  
Woo-Chang Kim ◽  
Hae-Ik Rhee ◽  
Boo-Kil Park ◽  
Kyoung-Ho Suk ◽  
Sang-Hoon Cha
Keyword(s):  
Cell Wall ◽  
Phage Display ◽  
Antibacterial Agents ◽  
Bacterial Resistance ◽  
Phage Display Library ◽  
Peptide Sequence ◽  
Membrane Function ◽  
Glutamate Racemase ◽  
Positive Phage

Several new antibacterial agents are currently being developed in response to the emergence of bacterial resistance to existing antibiotic substances. The new agents include compounds that interfere with bacterial membrane function. The peptidoglycan component of the bacterial cell wall is synthesized by glutamate racemase, and this enzyme is responsible for the biosynthesis of d-glutamate, which is an essential component of cell wall peptidoglycan. In this study, we screened a phage display library expressing random dodecapeptides on the surface of bacteriophage against an Escherichia coli glutamate racemase, and isolated specific peptide sequences that bind to the enzyme. Twenty-seven positive phage clones were analyzed, and seven different peptide sequences were obtained. Among them, the peptide sequence His-Pro-Trp-His-Lys-Lys-His-Pro-Asp-Arg-Lys-Thr was found most frequently, suggesting that this peptide might have the highest affinity to glutamate racemase. The positive phage clones and HPWHKKHPDRKT synthetic peptide were able to inhibit glutamate racemase activity in vitro, implying that our peptide inhibitors may be utilized for the molecular design of new potential antibacterial agents targeting cell wall synthesis.

Production, characterization and in-vitro applications of single-domain antibody against thyroglobulin selected from novel T7 phage display library

2021 ◽  
Vol 492 ◽  
pp. 112990
Author(s):  
Jothivel Kumarasamy ◽  
Samar Kumar Ghorui ◽  
Chandrakala Gholve ◽  
Bharti Jain ◽  
Yogesh Dhekale ◽  
...  
Keyword(s):  
Phage Display ◽  
Phage Display Library ◽  
Single Domain ◽  
Single Domain Antibody ◽  
Domain Antibody ◽  
T7 Phage Display ◽  
T7 Phage

The Activity of Alkanna Species in vitro Culture and Intact Plant Extracts Against Antibiotic Resistant Bacteria

2019 ◽  
Vol 25 (16) ◽  
pp. 1861-1865 ◽  
Author(s):  
Naira Sahakyan ◽  
Margarit Petrosyan ◽  
Armen Trchounian
Keyword(s):  
Antibiotic Resistance ◽  
Antibacterial Agents ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Resistant Bacteria ◽  
Plant Origin ◽  
Bacterial Strains ◽  
Biotechnological Production ◽  
Antibiotic Resistant

Overcoming the antibiotic resistance is nowadays a challenge. There is still no clear strategy to combat this problem. Therefore, the urgent need to find new sources of antibacterial agents exists. According to some literature, substances of plant origin are able to overcome bacterial resistance against antibiotics. Alkanna species plants are among the valuable producers of these metabolites. But there is a problem of obtaining the standardized product. So, this review is focused on the discussion of the possibilities of biotechnological production of antimicrobial agents from Alkanna genus species against some microorganisms including antibiotic resistant bacterial strains.

scholarly journals BAR Domain Proteins Rvs161 and Rvs167 Contribute to Candida albicans Endocytosis, Morphogenesis, and Virulence

2009 ◽  
Vol 77 (9) ◽  
pp. 4150-4160 ◽  
Author(s):  
Lois M. Douglas ◽  
Stephen W. Martin ◽  
James B. Konopka
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Plasma Membrane ◽  
Antifungal Drugs ◽  
Host Immune System ◽  
Membrane Function ◽  
Histatin 5 ◽  
Essentially Normal ◽  
Altered Cell

ABSTRACT The Candida albicans plasma membrane plays critical roles in growth and virulence and as a target for antifungal drugs. Three C. albicans genes that encode Bin-Amphiphysin-Rvs homology domain proteins were mutated to define their roles in plasma membrane function. The deletion of RVS161 and RVS167, but not RVS162, caused strong defects. The rvs161Δ mutant was more defective in endocytosis and morphogenesis than rvs167Δ, but both were strongly defective in polarizing actin patches. Other plasma membrane constituents were still properly localized, including a filipin-stained domain at the hyphal tips. An analysis of growth under different in vitro conditions showed that the rvs161Δ and rvs167Δ mutants grew less invasively in agar and also suggested that they have defects in cell wall synthesis and Rim101 pathway signaling. These mutants were also more resistant to the antimicrobial peptide histatin 5 but showed essentially normal responses to the drugs caspofungin and amphotericin. Surprisingly, the rvs161Δ mutant was more sensitive to fluconazole, whereas the rvs167Δ mutant was more resistant, indicating that these mutations cause overlapping but distinct effects on cells. The rvs161Δ and rvs167Δ mutants both showed greatly reduced virulence in mice. However, the mutants were capable of growing to high levels in kidneys. Histological analyses of infected kidneys revealed that these rvsΔ mutants grew in a large fungal mass that was walled off by leukocytes, rather than forming disseminated microabscesses as seen for the wild type. The diminished virulence is likely due to a combination of the morphogenesis defects that reduce invasive growth and altered cell wall construction that exposes proinflammatory components to the host immune system.

scholarly journals Canine CD117-Specific Antibodies with Diverse Binding Properties Isolated from a Phage Display Library Using Cell-Based Biopanning

Antibodies ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 15 ◽  
Author(s):  
Mohamed Alfaleh ◽  
Neetika Arora ◽  
Michael Yeh ◽  
Christopher de Bakker ◽  
Christopher Howard ◽  
...  
Keyword(s):  
Phage Display ◽  
Ex Vivo ◽  
Phage Display Library ◽  
Cross Reactivity ◽  
Tyrosine Kinase Receptor ◽  
Binding Assays ◽  
Comparative Oncology ◽  
Whole Cells ◽  
Exposed Region

CD117 (c-Kit) is a tyrosine kinase receptor that is overexpressed in multiple dog tumors. There is 100% homology between the juxtamembrane domain of human and canine CD117, and many cancer-causing mutations occur in this region in both species. Thus, CD117 is an important target for cancer treatment in dogs and for comparative oncology studies. Currently, there is no monoclonal antibody (mAb) specifically designed to target the exposed region of canine CD117, although there exist some with species cross-reactivity. We panned a naïve phage display library to isolate antibodies against recombinant CD117 on whole cells. Several mAbs were isolated and were shown to bind recombinant canine CD117 at low- to sub-nanomolar affinity. Additionally, binding to native canine CD117 was confirmed by immunohistochemistry and by flow cytometry. Competitive binding assays also identified mAbs that competed with the CD117 receptor-specific ligand, the stem cell factor (SCF). These results show the ability of our cell-based biopanning strategy to isolate a panel of antibodies that have varied characteristics when used in different binding assays. These in vitro/ex vivo assessments suggest that some of the isolated mAbs might be promising candidates for targeting overexpressed CD117 in canine cancers for different useful applications.

scholarly journals Neutralizing Human Antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 Isolated from a Human Synthetic Fab Phage Display Library

2021 ◽  
Vol 22 (4) ◽  
pp. 1913
Author(s):  
Yu Jung Kim ◽  
Min Ho Lee ◽  
Se-Ra Lee ◽  
Hyo-Young Chung ◽  
Kwangmin Kim ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Phage Display ◽  
Viral Entry ◽  
Phage Display Library ◽  
Cross Reactivity ◽  
Spike Protein ◽  
Receptor Protein ◽  
In Vitro Assays ◽  
Global Threat

Since it was first reported in Wuhan, China, in 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic outbreak resulting in a tremendous global threat due to its unprecedented rapid spread and an absence of a prophylactic vaccine or therapeutic drugs treating the virus. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is a key player in the viral entry into cells through its interaction with the angiotensin-converting enzyme 2 (ACE2) receptor protein, and the RBD has therefore been crucial as a drug target. In this study, we used phage display to develop human monoclonal antibodies (mAbs) that neutralize SARS-CoV-2. A human synthetic Fab phage display library was panned against the RBD of the SARS-CoV-2 spike protein (SARS-2 RBD), yielding ten unique Fabs with moderate apparent affinities (EC50 = 19–663 nM) for the SARS-2 RBD. All of the Fabs showed no cross-reactivity to the MERS-CoV spike protein, while three Fabs cross-reacted with the SARS-CoV spike protein. Five Fabs showed neutralizing activities in in vitro assays based on the Fabs’ activities antagonizing the interaction between the SARS-2 RBD and ACE2. Reformatting the five Fabs into immunoglobulin Gs (IgGs) greatly increased their apparent affinities (KD = 0.08–1.0 nM), presumably due to the effects of avidity, without compromising their non-aggregating properties and thermal stability. Furthermore, two of the mAbs (D12 and C2) significantly showed neutralizing activities on pseudo-typed and authentic SARS-CoV-2. Given their desirable properties and neutralizing activities, we anticipate that these human anti-SARS-CoV-2 mAbs would be suitable reagents to be further developed as antibody therapeutics to treat COVID-19, as well as for diagnostics and research tools.

scholarly journals Broad Spectrum Antibacterial Ocotillol-Type Derivatives: Semi-Synthesis, Structure-Activity Relationship, and Membrane-Active Mode of Action

2021 ◽  
Author(s):  
Xianming Zeng ◽  
Ziyi Zhang ◽  
Yunyun Zhou ◽  
Shengyu Zhang ◽  
Zhiwen Zhou
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Bacterial Resistance ◽  
Synergistic Effects ◽  
Resistance Mechanism ◽  
Multidrug Resistant ◽  
Hek 293 ◽  
Low Cytotoxicity ◽  
New Compounds

A series of 3-amino substituted ocotillol-type derivatives were designed and synthesized for the first time. The in vitro antibacterial activity tests showed that some of the new compounds exhibited excellent antibacterial activity. Compound 13d, which was the most active one, displayed particularly strong antibacterial activity against S. aureus, B. subtilis, MRSA (methicillin-resistant S. aureus) and E. coli with minimum inhibitory concentration (MIC) values of 1-4 μg mL-1. Further research also suggested that 13d showed low cytotoxicity to human normal cells HEK-293 and L02, strong synergistic effects with kanamycin or chloramphenicol and a broad antibacterial spectrum including against multidrug-resistant strains. This active molecule 13d also induced bacterial resistance more slowly than norfloxacin and colistin. Furthermore, the research results demonstrated that this type of compounds could disperse the established bacterial biofilms, thus suppressing or delaying the development of drug resistance. Mechanism studies have shown that compound 13d could damage the integrity of cell membranes, which in turn facilitated the antibacterial agents binding to deoxyribonucleic acid (DNA), leading to cell death. Therefore, these results indicated that the membrane active ocotillol-type derivatives are a promising class of antibacterial agents to fight against super bacteria and deserve further attention.

scholarly journals Discovery and Development of Human SARS-CoV-2 Neutralizing Antibodies using an Unbiased Phage Display Library Approach

2020 ◽  
Author(s):  
Xia Cao ◽  
Junki Maruyama ◽  
Heyue Zhou ◽  
Lisa Kerwin ◽  
Rachel Sattler ◽  
...  
Keyword(s):  
Phage Display ◽  
Neutralizing Antibodies ◽  
Phage Display Library ◽  
Antibody Library ◽  
Hamster Model ◽  
Functional Profiling ◽  
Dose Dependent ◽  
Potent Protection

ABSTRACTSARS-CoV-2 neutralizing antibodies represent an important component of the ongoing search for effective treatment of and protection against COVID-19. We report here on the use of a naïve phage display antibody library to identify a panel of fully human SARS-CoV-2 neutralizing antibodies. Following functional profiling in vitro against an early pandemic isolate as well as a recently emerged isolate bearing the D614G Spike mutation, the clinical candidate antibody, STI-1499, and the affinity-engineered variant, STI-2020, were evaluated for in vivo efficacy in the Syrian golden hamster model of COVID-19. Both antibodies demonstrated potent protection against the pathogenic effects of the disease and a dose-dependent reduction of virus load in the lungs, reaching undetectable levels following a single dose of 500 micrograms of STI-2020. These data support continued development of these antibodies as therapeutics against COVID-19 and future use of this approach to address novel emerging pandemic disease threats.

scholarly journals Synthesis and Antibacterial Activity of Novel Schiff Bases of Thiosemicarbazone Derivatives With Adamantane Moiety

2021 ◽  
Author(s):  
Jiahui Zhu ◽  
Guosheng Teng ◽  
Dongfeng Li ◽  
Ruibin Hou ◽  
Yan Xia
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Bacterial Resistance ◽  
Inhibitory Effect ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Major Threat ◽  
Antibiotic Drugs

Abstract Increased bacterial resistance to antibiotics is a major threat to human health, and it is particularly important to develop novel antibiotic drugs. Here, we designed a series of Schiff base thiosemicarbazone derivatives containing an adamantane moiety, and carried out structural characterization of the compounds and in vitro antibacterial activity tests. Compound 7e was as effective as the commonly-used antibiotic ampicillin against the Gram-negative bacterium Escherichia coli, and compound 7g had a good inhibitory effect against Gram-positive Bacillus subtilis. These findings provide data for the development of better thiosemicarbazone antibacterial agents.

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