Specific disulfide formation in the oxidation of HIV-1 zinc finger protein nucleocapsid p7.
In vitro oxidation of the HIV-1 nucleocapsid protein p7 by the C-nitroso compound 3-nitrosobenzamide (NOBA) has been investigated. When reconstituted p7 was incubated with NOBA, three disulfide bonds were formed per molecule of p7, Cys 15-Cys 18, Cys 28-Cys 36, and Cys 39-Cys 49. These were identified using the proteolytic enzyme endoproteinase Lys-C and mass spectrometry. When the denatured protein (Apo-p7) was incubated with NOBA, a more random pattern of multiple S-S linkages was found. Oxidation of reconstituted p7 also occurred on treatment with cupric ions (Cu2+), and the same three major disulfide bonds were formed as in the reaction with NOBA. These results suggest the interpretation that the oxidation reaction occurs at the zinc-binding centers while zinc cations are still bound and that the two zinc fingers are not identical in their chemical properties. This latter point is consistent with the independent biological roles reported previously for the two fingers in the viral infection cycle.
Yu
X
X
Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228-5398, USA.
Hathout
Y
Y
Fenselau
C
C
Sowder
R C
RC
Henderson
L E
LE
Rice
W G
WG
Mendeleyev
J
J
Kun
E
E
D000595:Amino Acid Sequence; D001549:Benzamides / Q000737:chemistry; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D003300:Copper / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D015683:Gene Products, gag / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009603:Nitroso Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011489:Protein Denaturation; D014764:Viral Proteins; D016335:Zinc Fingers; D054301:gag Gene Products, Human Immunodeficiency Virus
D001549:Benzamides; D036022:Capsid Proteins; D004220:Disulfides; D015683:Gene Products, gag; C071884:NCP7 protein, Human immunodeficiency virus 1; D009603:Nitroso Compounds; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; D003300:Copper; C076039:3-nitrosobenzamide