title: Crystal structure of malaria parasite nucleosome assembly protein: distinct modes of protein localization and histone recognition.
abstract: Nucleosome assembly proteins (NAPs) are histone chaperones that are essential for the transfer and incorporation of histones into nucleosomes. NAPs participate in assembly and disassembly of nucleosomes and in chromatin structure organization. Human malaria parasite Plasmodium falciparum contains two nucleosome assembly proteins termed PfNapL and PfNapS. To gain structural insights into the mechanism of NAPs, we have determined and analyzed the crystal structure of PfNapL at 2.3 A resolution. PfNapL, an ortholog of eukaryotic NAPs, is dimeric in nature and adopts a characteristic fold seen previously for yeast NAP-1 and Vps75 and for human SET/TAF-1b (beta)/INHAT. The PfNapL monomer is comprised of domain I, containing a dimerization alpha-helix, and a domain II, composed of alpha-helices and a beta-subdomain. Structural comparisons reveal that the "accessory domain," which is inserted between the domain I and domain II in yeast NAP-1 and other eukaryotic NAPs, is surprisingly absent in PfNapL. Expression of green fluorescent protein-tagged PfNapL confirmed its exclusive localization to the parasite cytoplasm. Attempts to disrupt the PfNapL gene were not successful, indicating its essential role for the malaria parasite. A detailed analysis of PfNapL structure suggests unique histone binding properties. The crucial structural differences observed between parasite and yeast NAPs shed light on possible new modes of histone recognition by nucleosome assembly proteins.
authors.affiliation: Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi 110067, India.
authors.forename: Jasmita
authors.initials: J
authors.lastname: Gill
authors.forename: Manickam
authors.initials: M
authors.lastname: Yogavel
authors.forename: Anuj
authors.initials: A
authors.lastname: Kumar
authors.forename: Hassan
authors.initials: H
authors.lastname: Belrhali
authors.forename: S K
authors.initials: SK
authors.lastname: Jain
authors.forename: Melanie
authors.initials: M
authors.lastname: Rug
authors.forename: Monica
authors.initials: M
authors.lastname: Brown
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Maier
authors.forename: Amit
authors.initials: A
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D018360:Crystallography, X-Ray / Q000379:methods; D006657:Histones / Q000737:chemistry; D006801:Humans; D008288:Malaria; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000737:chemistry*; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D006657:Histones; D009707:Nucleosomes