342 Abstracts MO15 GENETIC AND STRUCTURAL STUDIES ON THE BACTERIOFERRITIN OF ESCHERICHIA COLI. S.C.Andrews, J.M.A.Smith, J.R.Guest & P.M.Harrison, Department of Molecular Biology and Biotechnology, The University, Sheffield SlO 2TN, U.K. The gene for the bacterioferritin (BFR) of E.coli, an iron-storage hemoprotein, has been cloned, sequenced, mapped and over-expressed. The primary translation product consists of 158 amino acids residues giving an 4 of 18,495. Secondary structure prediction suggests a high ~1- helical content for BFR consistent with a four helix-bundle motif, as in mammalian apoferritins and also in cytochromes b562 (E.coli) and c' (Rhodospirillum molischianum). Crystallographic data indicate that BFR like mammalian apoferritins is a shell of 24 subunits in 432 symmetry. Their primary structures, however, show little similarity. MO16 ~i~~;;LF~~MPOUND FOR THE Zn BlNBfNG SiTE Of- Zn rINGE!S CJ Robert Bau, Dept. of Chemistry, Unlvers1t.y of Southern California: Los Angeles, GA 90039-0744. Recently, it has been revealed that DNA binding proteins of many viruses and ba teria contain Zn fingers, 30 amino acids 1 . t, a Zn binding domain of about Zn fingers are believed to control the strucutures of DNA binding proteins, which bind to DNA and initiate DNA polymeriza- tion. We synthesized the Zn complex of 1,3-Bis-(2'-pyridyl)-3,6-Dithia- octane as a model for the Zn binding site of Zn fingers. The structure the model compound was determined from single-crystal X-ray analysis. The structural details of the model compound and its structural varia- tion upon coordination to phosphonoformic acid(PFA), an anti-aids agent, as well as their biological implications will be discussed. (1) Klug, A. & Rhoades, D., Trends Biochem. Sci. J2_ 464 (1987) MO17 SYNTKETIC AND SPECTROSCOPIC MODELS FOR ZINC-CYSTEINE CENTERS IN ZINC FINGER PROTEINS AND OTHER ZINC-CONTAINING PROTEINS. Stephen A. Koch, Eric Gruff, Douglas Corwin, Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 USA Zinc@-cys), (x = l-4) coordination centers have proposed or established in a wide range of metalloproteins including the recently discovered zinc finger proteins. A series of [Zn(SR),(imidazole)4_x] complexes have been synthesized to serve as structural models for the protein centers. Analogous cobalt(Il) and cadmium(I1) complexes have been prepared to serve as spectroscopic models for metal substituted zinc centers. Structural and spectroscopic criterion have been established which should enable the identification of the coordination number and geometry of zinc-cysteine centers in metalloproteins and for the determination of the number of cysteine residues coordinated to these centers.

Synthetic and spectroscopic models for zinc-cysteine centers in zinc finger proteins and other zinc-containing proteins

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Page 1: Synthetic and spectroscopic models for zinc-cysteine centers in zinc finger proteins and other zinc-containing proteins

342 Abstracts

MO15 GENETIC AND STRUCTURAL STUDIES ON THE BACTERIOFERRITIN OF

ESCHERICHIA COLI. S.C.Andrews, J.M.A.Smith, J.R.Guest & P.M.Harrison, Department of Molecular Biology and Biotechnology, The

University, Sheffield SlO 2TN, U.K.

The gene for the bacterioferritin (BFR) of E.coli, an iron-storage

hemoprotein, has been cloned, sequenced, mapped and over-expressed. The primary translation product consists of 158 amino acids residues giving

an 4 of 18,495. Secondary structure prediction suggests a high ~1-

helical content for BFR consistent with a four helix-bundle motif, as

in mammalian apoferritins and also in cytochromes b562 (E.coli) and c'

(Rhodospirillum molischianum). Crystallographic data indicate that BFR

like mammalian apoferritins is a shell of 24 subunits in 432 symmetry.

Their primary structures, however, show little similarity.

MO16 ~i~~;;LF~~MPOUND FOR THE Zn BlNBfNG SiTE Of- Zn rINGE!S CJ Robert Bau, Dept. of Chemistry, Unlvers1t.y of

Southern California: Los Angeles, GA 90039-0744. Recently, it has been revealed that DNA binding proteins of many

viruses and ba teria contain Zn fingers, 30 amino acids 1 . t,

a Zn binding domain of about Zn fingers are believed to control the strucutures

of DNA binding proteins, which bind to DNA and initiate DNA polymeriza- tion. We synthesized the Zn complex of 1,3-Bis-(2'-pyridyl)-3,6-Dithia- octane as a model for the Zn binding site of Zn fingers. The structure the model compound was determined from single-crystal X-ray analysis. The structural details of the model compound and its structural varia- tion upon coordination to phosphonoformic acid(PFA), an anti-aids agent, as well as their biological implications will be discussed.

(1) Klug, A. & Rhoades, D., Trends Biochem. Sci. J2_ 464 (1987)

MO17 SYNTKETIC AND SPECTROSCOPIC MODELS FOR ZINC-CYSTEINE CENTERS IN ZINC FINGER PROTEINS AND OTHER ZINC-CONTAINING

PROTEINS. Stephen A. Koch, Eric Gruff, Douglas Corwin, Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 USA

Zinc@-cys), (x = l-4) coordination centers have proposed or established in a wide range of metalloproteins including the recently discovered zinc finger proteins. A series of [Zn(SR),(imidazole)4_x] complexes have been synthesized to serve as structural models for the protein centers. Analogous cobalt(Il) and cadmium(I1) complexes have been prepared to serve as spectroscopic models for metal substituted zinc centers. Structural and spectroscopic criterion have been established which should enable the identification of the coordination number and geometry of zinc-cysteine centers in metalloproteins and for the determination of the number of cysteine residues coordinated to these centers.