Dimerization of the tat protein from human immunodeficiency virus: a cysteine-rich peptide mimics the normal metal-linked dimer interface.
We have synthesized an 18-amino acid peptide that contains the cysteine-rich region of the tat protein from human immunodeficiency virus. Previous experiments in vitro with the intact tat protein have shown that these cysteines serve as metal ligands, causing tat to form metal-linked dimers. Ultraviolet absorption spectra show that the synthetic peptide (tat21-38) binds two Cd2+ or two Zn2+ ions per peptide monomer, and some changes in the circular dichroism spectra are seen as the metals bind. The peptide-metal complexes are completely resistant to proteolytic digestion, and mass spectrometry demonstrates that this peptide forms metal-linked dimers. The peptide can also combine with the intact tat protein to form metal-linked heterodimers. If these heterodimers are unable to trans-activate viral transcription, tat21-38 could be a lead compound for designing drugs to treat acquired immunodeficiency syndrome.
Frankel
A D
AD
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Chen
L
L
Cotter
R J
RJ
Pabo
C O
CO
D000595:Amino Acid Sequence; D002104:Cadmium / Q000378:metabolism*; D002942:Circular Dichroism; D003545:Cysteine; D015696:Gene Products, tat; D006678:HIV / Q000378:metabolism*; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D014157:Transcription Factors / Q000138:chemical synthesis / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D046911:Macromolecular Substances; D009842:Oligopeptides; D014157:Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D002104:Cadmium; D015032:Zinc; D003545:Cysteine