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Publication Abstract from PubMed

The ATP-dependent caseinolytic protease, ClpP, is highly conserved in bacteria and in the organelles of different organisms. In cyanobacteria, plant plastids, and the apicoplast of the genus Plasmodium, a non-catalytic paralog of ClpP, termed ClpR, has been identified. ClpRs are found to form heterocomplexes with ClpP resulting in a ClpRP tetradecameric cylinder having less than 14 catalytic triads. The exact role of ClpR in such a complex remains enigmatic. Here we describe the X-ray crystal structure of ClpR protein heptamer from Plasmodium falciparum (PfClpR). This is the first structure of a ClpR protein. The structure shows that PfClpR monomer adopts a fold similar to that of ClpP, but has a unique motif, which we named the R motif, forming a beta turn located near the inactive catalytic triad in 3D space. The PfClpR heptamer exhibits a more open and flat ring than a ClpP heptamer. PfClpR was localized in the P. falciparum apicoplast as is the case of PfClpP. However, biochemical and structural data suggest that, contrary to what has been observed in other organisms, PfClpP and PfClpR do not form a stable heterocomplex in the apicoplast of P. falciparum.

Structural insights into the inactive subunit of the apicoplast-localized caseinolytic protease complex of Plasmodium falciparum.,El Bakkouri M, Rathore S, Calmettes C, Wernimont AK, Liu K, Sinha D, Asad M, Jung P, Hui R, Mohmmed A, Houry WA J Biol Chem. 2012 Nov 28. PMID:23192353^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.