of cytochrome c3 proteins (which are known to have three conformationally distinct electrochemical forms) adsorbed on Hg electrodes. The proteins studied were wild-type cytochrome c3 and two mutants (H70M and H70V) in which one of the heme axial ligands is replaced by methionine or valine, respectively. To probe the protein orientation and conformational change, all antibodies must bind to all non-native conformations induced by the adsorption on the electrode. An antibody that binds to a conformational epitope (a discontinuous epitope formed from residues adjacent in space but not necessarily in the sequence) will be most sensitive to the conformational changes. The authors determined that the antibodies 2A2 and 4H8 were sensitive to the potential dependent conformational changes of the absorbed cytochrome c3. The binding constants of the antibodies to cytochrome c3 were used to determine that the protein does indeed have three conformations at the various potentials. These results were confirmed by a separate radioimmunoassay. (J. Am. .hem. Soc. 1997,119, 5295-301)
BUSINESS
Andi protocols now under ASTM The responsibility for standardizing the instrumental reporting of analytical data, known as the Andi (analytical data interchange) Protocols, has been transferred from the Analytical Instrument Association (ALA) to the American Society for Testing and Materials (ASTM). According to Michael Duff, executive director of ALA, the association decided on the move because "it wanted the protocols to reside in an organization that can maintain them and test them." In addition Duff said that ASTM will bring software writers government scientists and instrument users into the protocol development process Andi was begun by AIA in efforts to make the analytical instrumentation as flexible as PCs in using software and equipment from various vendors (Anal. Chem. 1997,68,529 A). To od that, instruments needed a common language, similar to DOS or UNIX in the PC world. AIA had some success in developing data protocols for chromatography, MS, and
The image of copper In metal electrodeposition and etching applications, controlling the surface morphology is critical. Allhough organic additives are often used for control, their influence on the development of surfaces is poorly understood because few techniques can measure the interaction of the additive with the surface and simultaneously characterize the changes in deposit morphology. Dean S. Chung and Richard C. Alkire at the University of Illinois at Urbana-Champaign used confocal laser scanning microscopy in situ during copper electrodeposition and electrodissolution to track the adsorption of thefluorescentcarbocyanine dye DiOC while simultaneously monitoring the changing surface morphology Their data showed that, with and without copper, the dye adsorbed to polycrystalline gold and inhibited cathodic processes. Without copper, dye adsorption on gold remained unaffected by changes in cathodic potential up to -750 mV. During copper electrodeposition at -550 and -650 mV, the adsorbed dye restricted nucleation of the copper to a few active sites
IR. However, AIA was limited in how much it could develop the protocols. According to Duff, AIA voted to approach ASTM with the request to take over the development of the protocols. Details of how ASTM will handle the Andi protocols were not available at press time, but the protocols are expected to fall under Committee E-49 on Computerized Systems and Material and Chemical Information. ASTM expects to develop consensus documents on the protocols. Moreover, says Duff, ASTM will be able to sponsor round-robin testing and updates of the protocols as needed. Alan Newman
Varian buys Chemagnetics California-based Varian Associates has purchased Chemagnetics, manufacturer of solid-state NMR instruments, from its parent owner Otsuka Electronics. According to Varian, the purchase is a complementaryfitto its other lines of NMR systems. Varian plans to continue to operate Chemagnetics's Ft. Collins, CO, manufacturing facility as part of its overall NMR business.
Confocal laser scanning microscopy morphology map of the electrodeposition no copper on gold in a solution of DiOC6 dye end copper sulfate at -550 mV. .Adapted with permission from J. Electtochem. Soc. Copyright 1997 Thh Electrochemical Society.)
and dye adsorption was maintained across areas where nucleation had not occurred. Secondary ion MS indicated that the dye, or a derivative of it, was incorporated into the deposit during copper electrodeposition. (J. Electrochem. Soc. 1997,144, 1529-36)
MEETING NEWS
News from ASMS Celia Henry reports from Palm Springs, CA A sampling of research presented at the 1997 meeting of the American Society for Mass Spectrometry
MALDI on a chip First there was the "lab on a chip"; then there was "sequencing on a chip". Now, take low-nanoliter volumes of analytes, dispense them into a small well of a lessthan-one-inch-sized substrate, analyze them by MS, and—voila—you have "MALDI on a chip". The technique was described by Daniel P. Little of Sequenom (San Diego, CA). MALDI on a chip was used to analyze products based on a molecular biology technique known as primer oligo base extension, or PROBE reaction, for largescale DNA diagnostics. The polymerase chain reaction is first used to replicate a strand of DNA. The strand is placed on a solid support, and a short piece of DNA is annealed close to the mutation site. The
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