Interaction of KMP-11 with Phospholipid Membranes and Its Implications in Leishmaniasis: Effects of Single Tryptophan Mutations and Cholesterol

Sannigrahi, Achinta and Maity, Pabitra and Karmakar, Sanat and Chattopadhyay, Krishnananda (2017) Interaction of KMP-11 with Phospholipid Membranes and Its Implications in Leishmaniasis: Effects of Single Tryptophan Mutations and Cholesterol. The Journal of Physical Chemistry B, 121 (8). pp. 1824-1834.

[img]

PDF
Restricted to IICB Scientists only

Download (4Mb) | Request a copy

    Abstract

    KMP-11 is a small protein that is believed to control the overall bilayer pressure of the Leishmania parasite.Recent results have suggested that membrane binding and the presence of cholesterol affect the efficacy of Leishmanial infection, in which KMP-11 plays an important role. Nevertheless, there exists no systematic study of membrane interaction with KMP-11 either in the absence or presence of cholesterol. In this article, we investigated the interaction between KMP-11 and phospholipid membranes using an unsaturated (PC 18:1; 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and saturated (PC 12:0; 1,2-dilauroyl-snglycero- 3-phosphocholine (DLPC)) lipid as membrane mimics. Additionally, we studied the effect of cholesterol on the protein−membrane interaction. Steady-state as well as timeresolved fluorescence spectroscopy, isothermal titration calorimetry (ITC), and ζ-potential measurements were used for the determination of the binding constants for the wild-type (WT) and single-site tryptophan mutants. Single-site tryptophan mutants were designed to make sure that the tryptophan residues sample different surface exposures in different mutants. In the absence of cholesterol, the membrane-binding affinities of the partially exposed and buried tryptophan mutants (Y5W and Y48W, respectively) were found to be greater than those of the WT protein. In the presence of cholesterol, the binding constants of the WT and Y48W mutant were found to decrease with an increase in cholesterol concentration. This was in contrast to that in the Y5W and F77W mutants, in which the binding constants increased on adding cholesterol. The present study highlights the interplay among the conformational architecture of a protein, its interaction with the membrane, and membrane composition in modulating the survival of a Leishmania parasite inside host macrophages.

    Item Type: Article
    URI: http://www.eprints.iicb.res.in/id/eprint/2646
    Subjects: Structural Biology & Bioinformatics
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Ms Sutapa Ganguly
    Date Deposited: 12 May 2017 15:07
    Last Modified: 12 May 2017 15:07
    Official URL: http://dx.doi.org/10.1021/acs.jpcb.6b11948
    Links:

    Actions (login required)

    View Item