title: P. falciparum cpn20 is a bona fide co-chaperonin that can replace GroES in E. coli.
abstract: Human malaria is among the most ubiquitous and destructive tropical, parasitic diseases in the world today. The causative agent, Plasmodium falciparum, contains an unusual, essential organelle known as the apicoplast. Inhibition of this degenerate chloroplast results in second generation death of the parasite and is the mechanism by which antibiotics function in treating malaria. In order to better understand the biochemistry of this organelle, we have cloned a putative, 20 kDa, co-chaperonin protein, Pf-cpn20, which localizes to the apicoplast. Although this protein is homologous to the cpn20 that is found in plant chloroplasts, its ability to function as a co-chaperonin was questioned in the past. In the present study, we carried out a structural analysis of Pf-cpn20 using circular dichroism and analytical ultracentrifugation and then used two different approaches to investigate the ability of this protein to function as a co-chaperonin. In the first approach, we purified recombinant Pf-cpn20 and tested its ability to act as a co-chaperonin for GroEL in vitro, while in the second, we examined the ability of Pf-cpn20 to complement an E. coli depletion of the essential bacterial co-chaperonin GroES. Our results demonstrate that Pf-cpn20 is fully functional as a co-chaperonin in vitro. Moreover, the parasitic co-chaperonin is able to replace GroES in E. coli at both normal and heat-shock temperatures. Thus, Pf-cpn20 functions as a co-chaperonin in chaperonin-mediated protein folding. The ability of the malarial protein to function in E. coli suggests that this simple system can be used as a tool for further analyses of Pf-cpn20 and perhaps other chaperone proteins from P. falciparum.
authors: George E. Wise Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University, Ramat Aviv, Israel.
authors: Anna
authors: A
authors: Vitlin Gruber
authors: Shahar
authors: S
authors: Nisemblat
authors: Gal
authors: G
authors: Zizelski
authors: Avital
authors: A
authors: Parnas
authors: Ron
authors: R
authors: Dzikowski
authors: Abdussalam
authors: A
authors: Azem
authors: Celeste
authors: C
authors: Weiss
mesh_terms: D018835:Chaperonin 10 / Q000737:chemistry / Q000378:metabolism; D018833:Chaperonins / Q000737:chemistry* / Q000235:genetics; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D002942:Circular Dichroism; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D006801:Humans; D008288:Malaria / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology; D015388:Organelles / Q000235:genetics / Q000378:metabolism; D010963:Plasmodium falciparum / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D018835:Chaperonin 10; D015800:Protozoan Proteins; D018833:Chaperonins