Annapurna  Jagarlamudi

A. A. Isab

C. Frank Shaw III

A.  Munoz

Formation and Reactivity of <svg style="vertical-align:-3.27605pt" height="20.8125" version="1.1" viewBox="0 0 99.099998 20.8125" width="99.099998" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,16.675)"><path id="x5B" d="M290 -163h-170v866h170v-28q-79 -7 -94 -19.5t-15 -72.5v-627q0 -59 14.5 -71.5t94.5 -19.5v-28z" /></g><g transform="matrix(.017,-0,0,-.017,5.927,16.675)"><path id="x41" d="M673 0h-245v28q47 6 58 16t1 39l-55 154h-213q-31 -87 -36 -129q-16 -47 -5 -61t68 -19v-28h-226v28q50 7 68.5 23.5t43.5 80.5l214 524l24 9l193 -536q23 -63 41.5 -79.5t68.5 -21.5v-28zM418 280l-81 255h-2q-74 -197 -101 -255h184z" /></g><g transform="matrix(.017,-0,0,-.017,16.976,16.675)"><path id="x75" d="M518 50v-26q-32 -4 -77 -16l-37 -11t-33 -9l-6 6v71q-56 -42 -74 -52q-43 -25 -77 -25q-55 0 -89.5 36.5t-34.5 112.5v196q0 38 -6.5 48.5t-26.5 15.5l-28 6v23q19 1 72 7q59 9 71 11q-3 -31 -3 -145v-135q0 -113 88 -113q59 0 108 48v234q0 38 -8 49t-34 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<svg style="vertical-align:-3.3907pt" height="20.950001" version="1.1" viewBox="0 0 129.27499 20.950001" width="129.27499" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,16.675)"><use xlink:href="#x5B"/></g><g transform="matrix(.017,-0,0,-.017,5.927,16.675)"><use xlink:href="#x41"/></g><g transform="matrix(.017,-0,0,-.017,16.976,16.675)"><use xlink:href="#x75"/></g><g transform="matrix(.017,-0,0,-.017,26.003,16.675)"><use xlink:href="#x28"/></g><g transform="matrix(.012,-0,0,-.012,31.887,8.513)"><use xlink:href="#x31"/></g><g transform="matrix(.012,-0,0,-.012,37.599,8.513)"><use xlink:href="#x33"/></g><g transform="matrix(.017,-0,0,-.017,43.925,16.675)"><use xlink:href="#x43"/></g><g transform="matrix(.017,-0,0,-.017,55.229,16.675)"><use xlink:href="#x4E"/></g><g transform="matrix(.017,-0,0,-.017,67.859,16.675)"><use xlink:href="#x29"/></g><g transform="matrix(.012,-0,0,-.012,73.75,20.75)"><use xlink:href="#x33"/></g><g transform="matrix(.017,-0,0,-.017,80.075,16.675)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,85.957,16.675)"><path id="x53" d="M409 504l-29 -5q-16 60 -44.5 96t-86.5 36q-54 0 -82.5 -32t-28.5 -77q0 -51 30.5 -82.5t96.5 -65.5l35.5 -18t33 -19.5t33.5 -23.5l27 -25.5t24.5 -32t13.5 -36.5t6 -45q0 -80 -62 -134.5t-160 -54.5q-47 0 -98 15q-22 7 -50 21q-8 23 -27 155l30 7q7 -27 18 -52&#xA;t30 -51.5t49 -42.5t67 -16q56 0 88 32.5t32 87.5q0 51 -31.5 82t-98.5 67q-80 44 -110 73q-55 53 -55 124q0 75 56 126.5t150 51.5q53 0 126 -23z" /></g><g transform="matrix(.017,-0,0,-.017,93.827,16.675)"><path id="x52" d="M631 18l-4 -26q-24 0 -35 1q-57 3 -92.5 23t-69.5 68q-21 30 -101 160q-13 22 -30.5 31t-54.5 9h-32v-159q0 -63 14 -77.5t74 -19.5v-28h-262v28q62 5 76 19.5t14 77.5v402q0 62 -13 76t-73 19v28h248q109 0 159 -34q67 -42 67 -131q0 -115 -127 -172q27 -52 89 -144&#xA;q49 -71 81 -104q31 -36 72 -47zM212 316h48q73 0 108 29q55 42 55 124q0 76 -42 112t-104 36q-41 0 -54 -10q-11 -7 -11 -44v-247z" /></g><g transform="matrix(.017,-0,0,-.017,104.383,16.675)"><use xlink:href="#x29"/></g><g transform="matrix(.012,-0,0,-.012,110.25,8.513)"><use xlink:href="#x28"/></g><g transform="matrix(.012,-0,0,-.012,114.375,8.513)"><use xlink:href="#x2D"/></g><g transform="matrix(.012,-0,0,-.012,118.6,8.513)"><use xlink:href="#x29"/></g><g transform="matrix(.017,-0,0,-.017,123.35,16.675)"><use xlink:href="#x5D"/></g></svg> Studied by <svg style="vertical-align:-0.20473pt" height="16.1" version="1.1" viewBox="0 0 23.475 16.1" width="23.475" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.012,-0,0,-.012,.062,7.613)"><use xlink:href="#x31"/></g><g transform="matrix(.012,-0,0,-.012,5.774,7.613)"><use xlink:href="#x33"/></g><g transform="matrix(.017,-0,0,-.017,12.112,15.775)"><use xlink:href="#x43"/></g></svg> NMR Spectroscopy

J.  Xiao

Gold(I) Weak Binding Sites: Histidine Residues of Serum Albumin

Rodney E. Sue

Peter J. Sadler

Alan  Tucker

Probing the Gold Binding Site in Serum Albumin

Jacqueline R. Roberts

Jun  Xiao

Brian  Schliesman

David J. Parsons

The Kinetics and Mechanism of the Reaction Between Serum Albuminand Auranofin (and its Isopropyl Analogue) <em>In Vitro</em>

Yafei  Zhang

Evelyn V. Hess

Keith G. Pryhuber

John G. Dorsey

Katherine  Tepperman

R. C. Elder

Interaction of Gold With Red Blood Cells

Three new findings are reviewed that help to understand the mechanisms ofaction of antirheumatic Au(I) drugs, such as disodium aurothiomalate (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Na</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mtext>Au</mml:mtext></mml:math>(I)TM):(i) We found that <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Na</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:mtext>Au</mml:mtext></mml:math>(I)TM selectively inhibits T cell receptor (TCR)-mediatedantigen recognition by murine <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>CD</mml:mtext><mml:msup><mml:mn>4</mml:mn><mml:mo>+</mml:mo></mml:msup></mml:math> T cell hybridomas specific for antigenic peptidescontaining at least two cysteine residues. Presumably, Au(I) acts as a chelatingagent forming linear complexes (Cys-Au(I)-Cys) which prevent correct antigen-processingand/or peptide recognition by the TCR. (ii) We were able to show thatAu(I) is oxidized to Au(III) in phagocytic cells, such as macrophages. Because Au(III)is re-reduced to Au(I) this may introduce an Au(I)/Au(III) redox system into phagocyteswhich scavenges reactive oxygen species, such as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mtext>OCl</mml:mtext><mml:mtext>-</mml:mtext></mml:msup></mml:math> and inactivateslysosomal enzymes. (iii) Pretreatment with Au(III) of a model protein antigen, bovineribonuclease A (RNase A), induced novel antigenic determinants recognized by<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>CD</mml:mtext><mml:msup><mml:mn>4</mml:mn><mml:mo>+</mml:mo></mml:msup></mml:math> T lymphocytes. Analysis of the fine specificity of these &#8216;Au(III)-specific&#8217; T cellsrevealed that they react to RNase peptides that are not presented to T cells when thenative protein, i.e., not treated with Au(III), is used as antigen. The T cell recognitionof these cryptic peptides did not require the presence of gold. This finding hasimportant implications for understanding the pathogenesis of allergic and autoimmuneresponses induced by Au(I) drugs. Taken together, our findings indicate thatAu(I) and Au(III) each exert specific effects on several distinct components ofmacrophages and the subsequent activation of T cells; these effects may explainboth the desired anti-inflammatory and the adverse effects of antirheumatic golddrugs.

Kazuo  Takahashi

Peter  Griem

Carsten  Goebel

Jose  Gonzalez

Ernst  Gleichmann

The Antirheumatic Drug Gold, a Coin With Two Faces: AU(I) and AU(III).Desired and Undesired Effects on the Immune System

Metallothionein is a ubiquitous protein with a wide range of proposed physiological roles, includingthe transport, storage and detoxification of essential and nonessential trace metals. The aminoacid sequence of isoform 2a of rabbit liver metallothionein, the isoform used in our spectroscopicstudies, includes 20 cysteinyl groups out of 62 amino acids. Metallothioneins in general representan impressive chelating agent for a wide range of metals. Structural studies carried out by anumber of research groups (using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mtext>H</mml:mtext><mml:mprescripts /><mml:none /><mml:mn>1</mml:mn></mml:mmultiscripts></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mtext>Cd</mml:mtext><mml:mprescripts /><mml:none /><mml:mn>113</mml:mn></mml:mmultiscripts></mml:math> NMR, X-ray crystallography, more recently EXAFS,as well as optical spectroscopy) have established that there are three structural motifs for metalbinding to mammalian metallothioneins. These three structures are defined by metal to proteinstoichiometric ratios, which we believe specifically determine the coordination geometry adoptedby the metal in the metal binding site at that metal to protein molar ratio. Tetrahedral geometry isassociated with the thiolate coordination of the metals in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mn>7</mml:mn></mml:msub></mml:math>-MT species, for M &#61; Zn(II), Cd(II),and possibly also Hg(II), trigonal coordination is proposed in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mrow><mml:mn>11</mml:mn><mml:mtext>-</mml:mtext><mml:mn>12</mml:mn></mml:mrow></mml:msub></mml:math>-MT species, for M &#61; Ag(I),Cu(I), and possibly also Hg(II), and digonal coordination is proposed for the metal in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mrow><mml:mn>17</mml:mn><mml:mtext>-</mml:mtext><mml:mn>18</mml:mn></mml:mrow></mml:msub></mml:math>-MTspecies for M &#61; Hg(II), and Ag(I). The <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mn>7</mml:mn></mml:msub></mml:math>-MT species has been completely characterized for M &#61;Cd(II) and Zn(II). <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mtext>Cd</mml:mtext><mml:mprescripts /><mml:none /><mml:mn>113</mml:mn></mml:mmultiscripts></mml:math> NMR spectroscopic and x-ray crystallographic data show that mammalian<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Cd</mml:mtext><mml:mn>7</mml:mn></mml:msub></mml:math>-MT and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Zn</mml:mtext><mml:mn>7</mml:mn></mml:msub></mml:math>-MT have a two domain structure, with metal-thiolate clusters of the form <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>S</mml:mtext><mml:mrow><mml:mtext>cys</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:msub></mml:math>(the &#945; domain) and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>M</mml:mtext><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>S</mml:mtext><mml:mrow><mml:mtext>cys</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>9</mml:mn></mml:mrow></mml:msub></mml:math> (the &#946; domain). A similar two domain structure involving <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Cu</mml:mtext><mml:mn>6</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>S</mml:mtext><mml:mrow><mml:mtext>cys</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:msub></mml:math>(&#945;) and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Cu</mml:mtext><mml:mn>6</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mtext>S</mml:mtext><mml:mrow><mml:mtext>cys</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>9</mml:mn></mml:mrow></mml:msub></mml:math> (&#946;) copper-thiolate clusters has been proposed for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Cu</mml:mtext><mml:mn>12</mml:mn></mml:msub></mml:math>-MT species.Copper-, silver- and gold-containing metallothioneins luminesce in the 500-600 nm region fromexcited triplet, metal-based states that are populated by absorption into the 260-300 nm region ofthe metal-thiolate charge transfer states. The luminescence spectrum provides a very sensitiveprobe of the metal-thiolate cluster structures that form when Ag(I), Au(I), and Cu(I) are added tometallothionein. CD spectroscopy has been used in our laboratory to probe the formation ofspecies that exhibit well-defined three-dimensional structures. Saturation of the optical signalsduring titrations of MT with Cu(I) or Ag(I) clearly show formation of unique metal-thiolate structuresat specific metal:protein ratios. However, we have proposed that these M&#61;7, 12 and 18 structuresform within a continuum of stoichiometries. Compounds prepared at these specific molar ratioshave been examined by X-ray Absorption Spectroscopy (XAS) and bond lengths have beendetermined for the metal-thiolate clusters through the EXAFS technique. The stoichiometric ratiodata from the optical experiments and the bond lengths from the XAS experiments are used topropose structures for the metal-thiolate binding site with reference to known inorganicmetal-thiolate compounds.

Martin J. Stillman

Anthony  Presta

Ziqi  Gui

De-Tong  Jiang

Spectroscopic Studies of Copper, Silver and Gold-Metallothioneins

Avarhusein A. Isab

M. Naseem Akhtar

Abdul Rahman Al-Arfaj


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Bis(Thiomalato)Gold(I) With Selenocyanate in an Aqueous Solution

Francesco  Caruso

J.  Tanski

M.  Rossi

C.  Smart

Synthesis and Characterization of Gold-Phosphine Complexes for Potential Use as Anti-Arthritic Agents

The redox chemistry of mononuclear and dinuclear gold(I) phosphine arylthiolate complexeswas recently investigated by using electrochemical, chemical, and photochemical techniques. Wenow report the redox chemistry of dinuclear gold(I) phosphine complexes containing aliphaticdithiolate ligands. These molecules differ from previously studied gold(I) phosphine thiolatecomplexes in that they are cyclic and contain aliphatic thiolates. Cyclic voltammetry experiments of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Au</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>(LL)(pdt) [pdt  &#61;  propanedithiol; LL &#61; 1,2-bis(diphenylphosphino)-ethane (dppe),1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb),1,5-bis(diphenylphosphino)pentane (dpppn)] in 0.1 M TBAH/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>CH</mml:mtext><mml:mn>3</mml:mn></mml:msub><mml:mtext>CN</mml:mtext></mml:math> or <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>CH</mml:mtext><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mtext>Cl</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math> solutions at 50 to500 mV/sec using glassy carbon or platinum electrodes, show two irreversible anodic processes atca. +0.6 and +1.1 V (vs. SCE). Bulk electrolyses at +0.9 V and +1.4 V result in n values of 0.95and 3.7, respectively. Chemical oxidation of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Au</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>(dppp)(pdt) using one equivalent of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Br</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>(2 oxidizing equivalents) yields 1,2-dithiolane and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Au</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>(dppp)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Br</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math>. The reactivity seen upon mildoxidation &#8804; +1.0 V is consistent with formal oxidation of a thiolate ligand, followed by a fastchemical reaction that results in cleavage of a second gold-sulfur bond. Oxidation at higherpotentials (&#8805; +1.3 V) is consistent with oxidation of gold(I) to gold(III). Structural andelectrochemical differences between gold(I) aromatic and aliphatic thiolate oxidation processes arediscussed.

Tong  Jiang

Gang  Wei

Cristopher  Turmel

Alice E. Bruce

Mitchell R. M. Bruce

Redox Chemistry of Gold(I) Phosphine Thiolates: Sulfur-BasedOxidation

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