Open AccessFolding stability of the kinetoplastid membrane protein‐11 (KMP‐11) from Leishmania infantum
Author(s) -
Fuertes Miguel Angel,
Berberich Christof,
Lozano Rosa María,
GimenezGallego Guillermo,
Alonso Carlos
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00217.x
Subject(s) - leishmania infantum , leishmania , chemistry , membrane , crystallography , denaturation (fissile materials) , native state , biophysics , biology , biochemistry , parasite hosting , nuclear chemistry , world wide web , computer science
Kinetoplastid membrane protein‐11 (KMP‐11) is a major component of the cell surface of kinetoplastids, and acts as a potent B‐ and T‐cell immunogen during Leishmania infection. Here we report that the Leishmania infantum KMP‐11 secondary structure adopts mainly an α‐helical conformation at pH 7.5 and that its urea‐ and thermally‐induced unfolding constitute a fully reversible two‐step process. This allows estimation of a half‐denaturation temperature of ≈65 °C, a Δ G D H2O at 20 °C of ≈14.63 kJ·mol −1 , and an increment of the reaction heat of ≈183.92 kJ·mol −1 and an entropy of ≈543.4 J·mol −1 ·deg −1 , respectively, for the native‐denatured equilibrium of the KMP‐11 in solution. We also report that the KPM‐11 protein is induced to adopt a molten globule state at a pH range between pH 4 and pH 6. As a whole, the stability and the specific features of the denaturing effect induced by changes in pH are similar in KMP‐11 to various other lipoproteins.