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Title: Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors

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  1. (UNC)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Institutes of Health (NIH)
OSTI Identifier:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemistry-US; Journal Volume: 54; Journal Issue: (2) ; 01, 2015
Country of Publication:
United States

Citation Formats

Bosch, Dustin E., Siderovski, David P., and WVU). Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors. United States: N. p., 2015. Web. doi:10.1021/bi501226f.
Bosch, Dustin E., Siderovski, David P., & WVU). Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors. United States. doi:10.1021/bi501226f.
Bosch, Dustin E., Siderovski, David P., and WVU). 2015. "Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors". United States. doi:10.1021/bi501226f.
title = {Entamoeba histolytica RacC Selectively Engages p21-Activated Kinase Effectors},
author = {Bosch, Dustin E. and Siderovski, David P. and WVU)},
abstractNote = {},
doi = {10.1021/bi501226f},
journal = {Biochemistry-US},
number = (2) ; 01, 2015,
volume = 54,
place = {United States},
year = 2015,
month = 1
  • The growth of Entamoeba histolytica in microtiter plates in vitro in a variety of environments with reduced oxygen tensions is reported. With 3% O/sub 2/, 3% CO/sub 2/, and 94% N/sub 2/, the parasite growth in microtiter plates was identical to that in screw-capped culture tubes, as measured by (/sup 3/H)thymidine incorporation and by quantitative parasite counts. There were no significant differences between the drug concentrations necessary to inhibit parasite growth by 50% based on (/sup 3/H)thymidine incorporation vs those defined by quantitative parasite counts for the 15 antimicrobial agents tested (including seven drugs used for the treatment of amebiasis).more » This technique provides a reproducible method to quantitate the activity of potential antiamebic agents in vitro. The isotopic method should be of particular value in defining the metabolism of the parasite and effects of antimicrobial agents on it, whereas the morphologic method may be more valuable for workers with limited resources available to them.« less
  • No abstract prepared.
  • The sequencing of the genome of Entamoeba histolytica has allowed a reconstruction of its metabolic pathways, many of which are unusual for a eukaryote. Based on the genome sequence, it appears that amino acids may play a larger role than previously thought in energy metabolism, with roles in both ATP synthesis and NAD regeneration. Arginine decarboxylase may be involved in survival of E. histolytica during its passage through the stomach. The usual pyrimidine synthesis pathway is absent, but a partial pyrimidine degradation pathway could be part of a novel pyrimidine synthesis pathway. Ribonucleotide reductase was not found in the E.more » histolytica genome, but it was found in the close relatives Entamoeba invadens and Entamoeba moshkovskii, suggesting a recent loss from E. histolytica. The usual eukaryotic glucose transporters are not present, but members of a prokaryotic monosaccharide transporter family are present.« less
  • No abstract prepared.
  • Cysteine proteases (CP) are key pathogenesis and virulence determinants of protozoan parasites. Entamoeba histolytica contains at least 50 cysteine proteases; however, only three (EhCP1, EhCP2 and EhCP5) are responsible for approximately 90% of the cysteine protease activity in this parasite. CPs are expressed as inactive zymogens. Because the processed proteases are potentially cytotoxic, protozoan parasites have developed mechanisms to regulate their activity. Inhibitors of cysteine proteases (ICP) of the chagasin-like inhibitor family (MEROPS family I42) were recently identified in bacteria and protozoan parasites. E. histolytica contains two ICP-encoding genes of the chagasin-like inhibitor family. EhICP1 localizes to the cytosol, whereasmore » EhICP2 is targeted to phagosomes. Herein, we report two crystal structures of EhICP2. The overall structure of EhICP2 consists of eight {beta}-strands and closely resembles the immunoglobulin fold. A comparison between the two crystal forms of EhICP2 indicates that the conserved BC, DE and FG loops form a flexible wedge that may block the active site of CPs. The positively charged surface of the wedge-forming loops in EhICP2 contrasts with the neutral surface of the wedge-forming loops in chagasin. We postulate that the flexibility and positive charge observed in the DE and FG loops of EhICP2 may be important to facilitate the initial binding of this inhibitor to the battery of CPs present in E. histolytica.« less