Urea equilibrium unfolding of the major core protein of the retrovirus feline immunodeficiency virus and its tryptophan mutants.
Circular dichroism and fluorescence spectroscopy have been employed to study the urea unfolding mechanism of a recombinant form of the major core protein of feline immunodeficiency virus (FIV-rp24) and its native tryptophan mutants. The equilibrium denaturation curves indicate the existence of two transitions. The first unfolding transition most likely reflects the denaturation of the carboxy-terminal region of FIV-rp24. Consequently, the second transition, where the changes in fluorescence are produced, should reflect the denaturation of the amino-terminal region. If the intermediate observed upon urea denaturation is an on-pathway species, the data described herein can reflect the sequential and independent loss of structure of the two domains that this type of proteins possesses.
Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
B
B
Yélamos
E
E
Núñez
J
J
Gómez-Gutiérrez
C
C
Delgado
B
B
Pacheco
D L
DL
Peterson
F
F
Gavilanes
D002942:Circular Dichroism; D003001:Cloning, Molecular; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics; D016089:Immunodeficiency Virus, Feline / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D011489:Protein Denaturation; D017510:Protein Folding; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry; D014508:Urea / Q000494:pharmacology*; D014758:Viral Core Proteins / Q000737:chemistry*
D015683:Gene Products, gag; D014758:Viral Core Proteins; C074662:p24 protein, Feline immunodeficiency virus; D014364:Tryptophan; D014508:Urea