title: Folding stability of the kinetoplastid membrane protein-11 (KMP-11) from Leishmania infantum.
abstract: 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 alpha-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 approximately 65 degrees C, a delta GDH2O at 20 degrees C of approximately 14.63 kJ.mol-1, and an increment of the reaction heat of approximately 183.92 kJ.mol-1 and an entropy of approximately 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.
authors: Centro de Biología Molecular 'Severo Ochoa', Universidad Autónoma de Madrid, Cantoblanco, Spain. mafuertes@trasto.cbm.uam.es
authors: M A
authors: MA
authors: Fuertes
authors: C
authors: C
authors: Berberich
authors: R M
authors: RM
authors: Lozano
authors: G
authors: G
authors: Gimenez-Gallego
authors: C
authors: C
authors: Alonso
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D018314:Leishmania infantum / Q000737:chemistry*; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D015800:Protozoan Proteins / Q000737:chemistry*; D013816:Thermodynamics; D014508:Urea
chemical_list: D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C090009:kinetoplastid membrane protein 11, Leishmania donovani; D014508:Urea