title: Residue level description of in vivo self-association of Plasmodium falciparum P2.
abstract: Plasmodium falciparum P2 (PfP2) is a ribosomal stalk protein. It also performs extra ribosomal novel functions that seem to be associated with homo oligomerization . Previous in vitro studies have demonstrated that the protein has a high tendency to self-associate predominantly into an 8-mer. In vitro Heteronuclear Single Quantum Coherence (HSQC) of the pure recombinant protein (rPfP2) and its in-cell (Escherichia coli) HSQC spectrum has very similar features, indicating that the protein intrinsically, both inside the cell and under in vitro conditions, has similar aggregation tendencies. In view of this, we have characterized here the folding and concomitant self-association of rPfP2, using an in vitro dissociation-association strategy. We observed that the residue stretch, (Met31-Leu44) of the rPfP2, mapping to Met1-Leu14 of PfP2 protein acts as a nucleation site for helix formation and subsequent self-association. Further association appears to be driven by hydrophobic and complimentary electrostatic charge interactions on the surfaces formed. One stretch of rPfP2, (Ile97-Ala116), always remains floppy, and this may serve as "hinge" for protein segmental motions. Based on these, we have proposed a possible model for rPfP2 self-association into an 8-mer.
authors.affiliation: a Department of Chemical Sciences , Tata Institute of Fundamental Research , Mumbai , India .
authors.forename: Pushpa
authors.initials: P
authors.lastname: Mishra
authors.forename: Shobhona
authors.initials: S
authors.lastname: Sharma
authors.forename: Ramakrishna V
authors.initials: RV
authors.lastname: Hosur
mesh_terms: D008958:Models, Molecular; D010963:Plasmodium falciparum / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D017510:Protein Folding / Q000187:drug effects; D055503:Protein Multimerization; D015800:Protozoan Proteins / Q000737:chemistry* / Q000378:metabolism; D014508:Urea / Q000494:pharmacology
chemical_list: D015800:Protozoan Proteins; D014508:Urea