scholarly journals The distinct biochemical property enables thymidylate kinase as a drug target and participates in pyrimidine drug sensitivity in Candida albicans

2018 ◽  
Author(s):  
Chang-Yu Huang ◽  
Yee-Chun Chen ◽  
Betty A. Wu-Hsieh ◽  
Jim-Min Fang ◽  
Zee-Fen Chang
Keyword(s):  
Candida Albicans ◽  
Drug Target ◽  
Essential Gene ◽  
Critical Role ◽  
Unmet Need ◽  
Biochemical Property ◽  
Drug Resistant ◽  
Potential Drug ◽  
Thymidylate Kinase ◽  
Human Enzyme

AbstractThe ability to overcome drug resistance in outbreaks of Candida albicans infection is an unmet need in health management. Here, we investigated CDC8, which encodes thymidylate kinase (TMPK), as a potential drug target for the treatment of C. albicans infection. In this study, we found that the specific region spanning amino acids 106-123, namely, the Ca-loop of C. albicans TMPK (CaTMPK) contributes to the hyperactivity of this enzyme compared to the human enzyme (hTMPK) and to the utilization of deoxyuridine monophosphate (dUMP)/ deoxy-5-Fluorouridine monophosphate (5-FdUMP) as a substrate. Notably, CaTMPK but not hTMPK enables dUTP/5-FdUTP-mediated DNA toxicity in yeast. CRISPR-mediated deletion of this Ca-loop in C. albicans demonstrated the critical role of this Ca-loop in fungal growth and susceptibility to 5-Fluorouridine (5-FUrd). Moreover, pathogenic and drug-resistant C. albicans clones were similarly sensitive to 5-FUrd. Thus, this study not only identified a target site for the development of CaTMPK-selective drugs but also revealed 5-FUrd to be a potential drug for the treatment of C. albicans infection.Author summaryThe emergence of drug-resistant C. albicans strains is a serious medical concern that may be addressed by targeting an essential fungal enzyme. CDC8 encodes thymidylate kinase (TMPK), which is the key enzyme required for dTTP synthesis and is an essential gene for yeast growth. Therefore, the differences of TMPK between human and C. albicans can be a potential drug targeting site. This study defines a specific Ca-loop unique to CaTMPK from C. albicans, contributing to hyper-activity over human enzyme (hTMPK). CRSPR-edited deletion of this loop also suppressed the growth of C. albicans. Moreover, we present evidence that this loop enables dUMP utilization by CaTMPK, but not hTMPK. CaTMPK is also capable of using 5-FdUMP as a substrate, which contributes to 5-FUrd-mediated toxicity. Importantly, we found that many drug resistant pathogenic C. albicans isolates from patients are sensitive to 5-FUrd, which has not been used as a drug against fungal infection.

scholarly journals Prioritizing and modelling of putative drug target proteins of Candida albicans by system biology approach

2018 ◽  
Vol 65 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Tariq Ismail ◽  
Nighat Fatima ◽  
Syed Aun Muhammad ◽  
Syed Saoud Zaidi ◽  
Nisar Rehman ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Drug Target ◽  
Drug Targets ◽  
Cellular Localization ◽  
Critical Role ◽  
Human Microbiome ◽  
Genomic Analysis ◽  
Cellular Systems ◽  
Gut Flora ◽  
Target Proteins

Candida albicans (C. albicans) is one of the major source of nosocomial infections in human which may prove fatal in 30% of cases. The hospital acquired infection is very difficult to affectively treat due to the presence of drug resistant pathogenic strains, therefore there is a need to find alternative drug targets to cure this infection. In silico and computational level frame work was used to prioritize and establish antifungal drug targets of Candida albicans. The identification of putative drug targets was based on acquiring completely 5090 annotated genes of Candida albicans from available databases which was categorized into essential and non-essential genes. The result indicated 9% proteins were essential that could become potential candidates for intervention which might result in pathogen death. We studied cluster of orthologs and the subtractive genomic analysis of these essential proteins against human genome as a reference to minimize the side effects. It was seen that 14% of Candidal proteins were evolutionary related to the human proteins while 86% are non-human homologs. In next step for the selection of compatible drug targets, the non-human homologs were sequentially compared to human microbiome data to minimize the potential effects against gut flora which accumulated to 38% of essential genome. The sub-cellular localization of these candidate proteins in fungal cellular systems exhibited that 80% are cytoplasmic, 10% are mitochondrial and remaining 10 % are associated with cell wall. The role of these non-human and non-gut flora putative target proteins in Candidal biological pathways was studied and on the basis of their integrated and critical role 4-proteins were selected for molecular modeling.  For drug designing and development, five quality and reliable protein models with more than 70% homology were constructed. Our study will be an effective framework for drug target identifications of pathogenic microbial strains and development of new therapies against these infections.

scholarly journals A novel CRISPRi platform to study the role of essential genes in antifungal drug-resistant Candida albicans isolates

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Lauren Wensing ◽  
Rebecca Shapiro ◽  
Deeva Uthayakumar ◽  
Viola Halder ◽  
Jehoshua Sharma ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Transcriptional Repression ◽  
Drug Targets ◽  
Large Scale ◽  
Essential Gene ◽  
Essential Genes ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Drug Resistant ◽  
Fungal Organisms

With the emergence of antifungal resistant Candida albicans strains, the need for new antifungal drugs is critical in combating this fungal pathogen. Investigating essential genes in C. albicans is a vital step in characterizing putative antifungal drug targets. As some of these essential genes are conserved between fungal organisms, developed therapies targeting these genes have the potential to be broad range antifungals. In order to study these essential genes, classical genetic knockout or CRISPR-based approaches cannot be used as disrupting essential genes leads to lethality in the organism. Fortunately, a variation of the CRISPR system (CRISPR interference or CRISPRi) exists that enables precise transcriptional repression of the gene of interest without introducing genetic mutations. CRISPRi utilizes an endonuclease dead Cas9 protein that can be targeted to a precise location but lacks the ability to create a double-stranded break. The binding of the dCas9 protein to DNA prevents the binding of RNA polymerase to the promoter through steric hindrance thereby reducing expression. We recently published the novel use of this technology in C. albicans and are currently working on expanding this technology to large scale repression of essential genes. Through the construction of an essential gene CRISPRi-sgRNA library, we can begin to study the function of essential genes under different conditions and identify genes that are involved in critical processes such as drug tolerance in antifungal resistant background strains. These genes can ultimately be characterized as putative targets for novel antifungal drug development, or targeted as a means to sensitize drug-resistant strains to antifungal treatment.

scholarly journals Genome analyses of 174 strains of Mycobacterium tuberculosis provide insight into the evolution of drug resistance and reveal potential drug targets

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Helianthous Verma ◽  
Shekhar Nagar ◽  
Shivani Vohra ◽  
Shubhanshu Pandey ◽  
Devi Lal ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Target ◽  
Drug Targets ◽  
Type Species ◽  
Close Association ◽  
Drug Resistant ◽  
Potential Drug ◽  
Sequence Alignments ◽  
Content Type ◽  
Link Type

Mycobacterium tuberculosis is a known human pathogen that causes the airborne infectious disease tuberculosis (TB). Every year TB infects millions of people worldwide. The emergence of multi-drug resistant (MDR), extensively drug resistant (XDR) and totally drug resistant (TDR) M. tuberculosis strains against the first- and second-line anti-TB drugs has created an urgent need for the development and implementation of new drug strategies. In this study, the complete genomes of 174 strains of M. tuberculosis are analysed to understand the evolution of molecular drug target (MDT) genes. Phylogenomic placements of M. tuberculosis strains depicted close association and temporal clustering. Selection pressure analysis by deducing the ratio of non-synonymous to synonymous substitution rates (dN/dS) in 51 MDT genes of the 174 M . tuberculosis strains led to categorizing these genes into diversifying (D, dN/dS>0.70), moderately diversifying (MD, dN/dS=0.35–0.70) and stabilized (S, dN/dS<0.35) genes. The genes rpsL, gidB, pncA and ahpC were identified as diversifying, and Rv0488, kasA, ndh, ethR, ethA, embR and ddn were identified as stabilized genes. Furthermore, sequence similarity networks were drawn that supported these divisions. In the multiple sequence alignments of diversifying and stabilized proteins, previously reported resistance mutations were checked to predict sensitive and resistant strains of M. tuberculosis . Finally, to delineate the potential of stabilized or least diversified genes/proteins as anti-TB drug targets, protein–protein interactions of MDT proteins with human proteins were analysed. We predict that kasA (dN/dS=0.29), a stabilized gene that encodes the most host-interacting protein, KasA, should serve as a potential drug target for the treatment of TB.

scholarly journals Peptidyl-tRNA hydrolase and its critical role in protein biosynthesis

Microbiology ◽  
2006 ◽  
Vol 152 (8) ◽  
pp. 2191-2195 ◽  
Author(s):  
Gautam Das ◽  
Umesh Varshney
Keyword(s):  
Drug Target ◽  
Protein Biosynthesis ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Ester Bond ◽  
Potential Drug Target ◽  
Potential Drug ◽  
Single Class ◽  
Translation Factors ◽  
Cellular Factors

Peptidyl-tRNA hydrolase (Pth) releases tRNA from peptidyl-tRNA by cleaving the ester bond between the peptide and the tRNA. Genetic analyses using Escherichia coli harbouring temperature-sensitive Pth have identified a number of translation factors involved in peptidyl-tRNA release. Accumulation of peptidyl-tRNA in the cells leads to depletion of aminoacyl-tRNA pools and halts protein biosynthesis. Thus, it is vital for cells to maintain Pth activity to deal with the pollution of peptidyl-tRNAs generated during the initiation, elongation and termination steps of protein biosynthesis. Interestingly, while eubacteria possess a single class of peptidyl-tRNA hydrolase, eukaryotes possess several such activities, making Pth a potential drug target to control eubacterial infections. This review discusses the aspects of Pth that relate to its history and biochemistry and its physiological connections with various cellular factors.

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