Folding stability of the kinetoplastid membrane protein-11 (KMP-11) from Leishmania infantum.
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.
Fuertes
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MA
Centro de Biología Molecular 'Severo Ochoa', Universidad Autónoma de Madrid, Cantoblanco, Spain. mafuertes@trasto.cbm.uam.es
Berberich
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C
Lozano
R M
RM
Gimenez-Gallego
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G
Alonso
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C
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
D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C090009:kinetoplastid membrane protein 11, Leishmania donovani; D014508:Urea