Structure, localization and histone binding properties of nuclear-associated nucleosome assembly protein from Plasmodium falciparum.
BACKGROUND
Nucleosome assembly proteins (NAPs) are histone chaperones that are crucial for the shuttling and incorporation of histones into nucleosomes. NAPs participate in the assembly and disassembly of nucleosomes thus contributing to chromatin structure organization. The human malaria parasite Plasmodium falciparum contains two nucleosome assembly proteins termed PfNapL and PfNapS.


METHODS
Three-dimensional crystal structure of PfNapS has been determined and analysed. Gene knockout and localization studies were also performed on PfNapS using transfection studies. Fluorescence spectroscopy was performed to identify histone-binding sites on PfNapS. Extensive sequence and structural comparisons were done with the crystal structures available for NAP/SET family of proteins.


RESULTS
Crystal structure of PfNapS shares structural similarity with previous structures from NAP/SET family. Failed attempts to knock-out the gene for PfNapS from malaria parasite suggest essentiality in the parasite. GFP-fused PfNapS fusion protein targeting indicates cellular localization of PfNapS in the parasite nucleus. Fluorescence spectroscopy data suggest that PfNapS interacts with core histones (tetramer, octamer, H3, H4, H2A and H2B) at a different site from its interaction with linker histone H1. This analysis illustrates two regions on the PfNapS dimer as the possible sites for histone recognition.


CONCLUSIONS
This work presents a thorough analysis of the structural, functional and regulatory attributes of PfNapS from P. falciparum with respect to previously studied histone chaperones.
Gill
Jasmita
J
Structural and Computational Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Road, New Delhi, 110067, India.
Kumar
Anuj
A
Yogavel
Manickam
M
Belrhali
Hassan
H
Jain
S K
SK
Rug
Melanie
M
Brown
Monica
M
Maier
Alexander G
AG
Sharma
Amit
A
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000502:physiology; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D018360:Crystallography, X-Ray / Q000379:methods; D055786:Gene Knockout Techniques; D056488:Histone Chaperones / Q000737:chemistry* / Q000502:physiology; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000378:metabolism; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence
D056488:Histone Chaperones; D006657:Histones; D009707:Nucleosomes; D015800:Protozoan Proteins; C550383:nucleosome assembly protein S, Plasmodium falciparum