HTLV-I Tax is a zinc-binding protein: role of zinc in Tax structure and function.
We have examined the functional significance of the cysteine- and histidine-rich region (amino acids 22-53) of HTLV-I Tax. A modeling of this region suggests two possible overlapping zinc-finger-like motifs. Using a zinc blotting technique, we show that Tax binds zinc. An N-terminal deletion in Tax that removed this zinc-finger region abolished the ability to bind zinc. Site-directed mutagenesis was used to generate 10 separate mutations so as to discriminate between the two alternative zinc-binding structures. Each Tax mutant was studied for its ability to trans-activate the HTLV-I LTR. Five of the ten mutations inactivated trans-activation. Our results support that one of the two putative zinc fingers is an integral element of Tax structure.
Semmes
O J
OJ
Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Jeang
K T
KT
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D016356:Gene Products, tax / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D015368:Human T-lymphotropic virus 1 / Q000737:chemistry*; D008667:Metalloproteins / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010449:Peptide Mapping; D011487:Protein Conformation; D012091:Repetitive Sequences, Nucleic Acid; D013329:Structure-Activity Relationship; D015533:Transcriptional Activation; D015032:Zinc / Q000378:metabolism*
D016356:Gene Products, tax; D008667:Metalloproteins; D015032:Zinc