GAL4 transcription factor is not a zinc finger but forms a Zn(II) sub 2 Cys sub 6 binuclear cluster

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.6.2077· OSTI ID:6169799

Pan, T; Coleman, J E ^[1]

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1. Yale Univ., New Haven, CT (USA)

The DNA-binding domain of the transcription factor GAL4, consisting of the 62 N-terminal residues and denoted GAL4(62*), contains a Cys-Xaa{sub 2}-Cys-Xaa{sub 6}-Cys-Xaa{sub 6}-Cys-Xaa{sub 2}-Cys-Xaa{sub 6}-Cys motif, which has been shown previously to bind two Zn(II) or Cd(II) ions. Binding of Zn(II) or Cd(II) is essential for the recognition by GAL4 of the specific palindromic DNA sequence to which it binds upstream of genes for galactose-metabolizing enzymes, the UAS{sub G} sequence. On the basis of the {sup 113}Cd NMR chemical shifts of the two bound {sup 113}Cd(II) ions, we propose a binuclear cluster model for this Zn(II)-binding subdomain. {sup 1}H-{sup 113}Cd heteronuclear multiple-quantum NMR spectroscopy and phase-sensitive double-quantum filtered {sup 1}H correlation spectroscopy of the {sup 112}Cd(II)-and {sup 113}Cd(II)-substituted GAL4(62*) derivatives provide direct evidence that the two bound {sup 113}Cd(II) ions are coordinated only by the six cysteine residues, two of which form bridging ligands between the two {sup 113}Cd(II) ions. The latter can be identified from the pattern of {sup 1}H-{sup 113}Cd J coupling. Thus a binuclear metal ion cluster rather than a zinc finger is formed by the six cysteine residues of the GAL4 DNA-binding domain. This model can be directly applied to eight other fungal transcription factors which have been shown to contain similarly spaced Cys{sub 6} clusters. {sup 1}H NMR spectra of apo-GAL4(62*) suggest conformational fluctuation of the metal-binding subdomain upon removal of Zn(II) or Cd(II). Both Cd(II){sub 2}-and Zn(II){sub 2}-containing species of GAL4 can be formed, and the similar {sup 1}H NMR spectra similar conformations.

• OSTI ID: 6169799
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:6; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CADMIUM 113
CADMIUM ISOTOPES
CHEMICAL REACTIONS
CHEMICAL SHIFT
CROSS-LINKING
ELEMENTARY PARTICLES
EVEN-ODD NUCLEI
FERMIONS
HADRONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGANDS
MAGNETIC RESONANCE
METALLOPROTEINS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEONS
NUCLEOPROTEINS
ORGANIC COMPOUNDS
POLYMERIZATION
PROTEINS
PROTONS
RADIOISOTOPES
RESONANCE
STABLE ISOTOPES
TRANSCRIPTION FACTORS
YEARS LIVING RADIOISOTOPES
ZINC COMPOUNDS