Completing the folate biosynthesis pathway in Plasmodium falciparum: p-aminobenzoate is produced by a highly divergent promiscuous aminodeoxychorismate lyase

2013 ◽  
Vol 455 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Giovanni Magnani ◽  
Michela Lomazzi ◽  
Alessio Peracchi

We identified the aminodeoxychorismate lyase from Plasmodium falciparum. This enzyme participates in the biosynthesis of folate and could be a new target for antimalarial therapy. The enzyme has little similarity to its bacterial counterparts and shows a minor D-amino acid transaminase activity.

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
J. Santiago Mejia ◽  
Erik N. Arthun ◽  
Richard G. Titus

One approach to identify epitopes that could be used in the design of vaccines to control several arthropod-borne diseases simultaneously is to look for common structural features in the secretome of the pathogens that cause them. Using a novel bioinformatics technique, cysteine-abundance and distribution analysis, we found that many different proteins secreted by several arthropod-borne pathogens, includingPlasmodium falciparum, Borrelia burgdorferi, and eight species of Proteobacteria, are devoid of cysteine residues. The identification of three cysteine-abundance and distribution patterns in several families of proteins secreted by pathogenic and nonpathogenic Proteobacteria, and not found when the amino acid analyzed was tryptophan, provides evidence of forces restricting the content of cysteine residues in microbial proteins during evolution. We discuss these findings in the context of protein structure and function, antigenicity and immunogenicity, and host-parasite relationships.


1991 ◽  
Vol 11 (2) ◽  
pp. 963-971
Author(s):  
B Fenton ◽  
J T Clark ◽  
C M Khan ◽  
J V Robinson ◽  
D Walliker ◽  
...  

Merozoite surface antigen MSA-2 of the human parasite Plasmodium falciparum is being considered for the development of a malaria vaccine. The antigen is polymorphic, and specific monoclonal antibodies differentiate five serological variants of MSA-2 among 25 parasite isolates. The variants are grouped into two major serogroups, A and B. Genes encoding two different variants from serogroup A have been sequenced, and their DNA together with deduced amino acid sequences were compared with sequences encoded by other alleles. The comparison shows that the serological classification reflects differences in DNA sequences and deduced primary structure of MSA-2 variants and serogroups. Thus, the overall homologies of DNA and amino acid sequences are over 95% among variants in the same serogroup. In contrast, similarities between the group A variants and a group B variant are only 70 and 64% for DNA and amino acid sequences, respectively. We propose that the MSA-2 protein is encoded by two highly divergent groups of alleles, with limited additional polymorphism displayed within each group.


1993 ◽  
Vol 104 (4) ◽  
pp. 1129-1136 ◽  
Author(s):  
M. Kimura ◽  
Y. Yamaguchi ◽  
S. Takada ◽  
K. Tanabe

A Ca(2+)-ATPase gene was cloned from the genomic libraries of Plasmodium falciparum. From the deduced amino acid sequence of the gene, a 139 kDa protein with a total of 1228 amino acids was predicted. Sequence of a partial cDNA clone of the gene identified two introns near the 3′-end at the regions identical to the regions assumed for the Ca(2+)-ATPase gene of P. yoelii, a rodent malaria species. As compared with a variety of Ca(2+)-ATPases, the P. falciparum Ca(2+)-ATPase had the highest amino acid sequence homology (78%) to the P. yoelii Ca(2+)-ATPase, moderate homology (45-50%) to vertebrate sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases (SERCAs), and lowest homology (20%) to a plasma membrane Ca(2+)-ATPase. The P. falciparum protein conserved sequences and residues that are important for the function and/or structure of the organellar type Ca(2+)-ATPase, such as high affinity Ca(2+)-binding sites, fluorescein isothiocyanate (FITC)-binding regions, and the phosphorylation site, but the protein did not contain calmodulin-binding regions that occur in the plasma membrane type Ca(2+)-ATPase. Thus we concluded the cloned gene was the organellar type Ca(2+)-ATPase of P. falciparum. In a region between the phosphorylation site and FITC-binding region, the P. falciparum protein was about 200 residues longer than the rabbit SERCA and lacked a sequence that binds to phospholamban, a protein that regulates the activity of the rabbit SERCA.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
YUNI SETYANINGSIH ◽  
ABDUL LATIF ◽  
HENDRI ASTUTY ◽  
DIN SYAFRUDDIN ◽  
PUJI BUDI SETIA ASIH

Objective: This research aims to study the activity of a Streptomyces sp. fermentation product as an antimalarial modality in HepG2 cells.Methods: The effects of the product against Plasmodium falciparum 3D7 were examined using an in vitro technique parasite. The potency of theStreptomyces sp. fermentation product was examined by determining the half maximal inhibitory concentration (IC50), and the mechanism wasstudied using transmission electron microscopy (TEM). Toxicity tests were also conducted.Results: The Streptomyces sp. fermentation product had an IC50 of 0.001 μg/ml against the parasite, versus values of 0.054 and 0.022 μg/ml forquinidine and prodigiosin, respectively. TEM revealed no formation of hemozoin. The Streptomyces sp. fermentation product was non-toxic in HepG2cells based on its cytotoxicity concentration 50% of 1.380 μg/ml.Conclusion: The Streptomyces sp. fermentation product has potential as a potent and non-toxic antimalarial therapy.


2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Ying Dong ◽  
Shuping Liu ◽  
Yan Deng ◽  
Yanchun Xu ◽  
Mengni Chen ◽  
...  

Abstract Background Failed diagnoses of some falciparum malaria cases by RDTs are constantly reported in recent years. Plasmodium falciparum histidine-rich protein 2 (pfhpr2) gene deficiency has been found to be the major reason of RDTs failure in many countries. This article analysed the deletion of pfhpr2 gene of falciparum malaria cases isolated in Yunnan Province, China. Methods Blood samples from falciparum malaria cases diagnosed in Yunnan Province were collected. Plasmodium genomic DNA was extracted and the pfhrp2 gene exon2 region was amplified via nested PCR. The haplotype of the DNA sequence, the nucleic acid diversity index (PI) and expected heterozygosity (He) were analyzed. Count PfHRP2 amino acid peptide sequence repeat and its times, and predict the properties of PfHRP2 peptide chain reaction to RDTs testing. Results A total of 306 blood samples were collected, 84.9% (259/306) from which pfhrp2 PCR amplification products (gene exon2) were obtained, while the remaining 47 samples were false amplification. The length of the 250 DNA sequences ranged from 345 - 927 bp, with 151 haplotypes, with PI and He values of 0.169 and 0.983, respectively. The length of the PfHRP2 peptide chain translated from 250 DNA sequences ranged from 115 to 309 aa. All peptide chains had more than an amino acid codon deletion. All 250 PfHRP2 strands ended with a type 12 amino acid repeat, 98.0% (245/250) started with a type 1 repetition and 2.0% (5/250) with a type 2 repetition. The detection rate for type 2 duplicates was 100% (250/250). Prediction of RDT sensitivity of PfHRP2 peptide chains based on type 2 and type 7 repeats showed that 9.60% (24/250), 50.0% (125/250), 13.20% (33/250) and 27.20.5% (68/250) of the 250 peptide chains were very sensitive, sensitive, borderline and non-sensitive, respectively. Conclusion The diversified polymorphism of the pfhrp2 gene deletion from different infection sources in the Yunnan province are extremely complex. The cause of the failure of pfhrp2 exon2 amplification is still to be investigated. The results of this study appeal to Yunnan Province for a timely evaluation of the effectiveness and applicability of RDTs in the diagnosis of malaria.


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