The interests of the Laboratory cover a wide range of systems and techniques relevant to macromolecular crystallography and its applications. The Synchrotron Radiation Research Section, based at the Advanced Photon Source at Argonne National Laboratory and headed by Dr. Zbigniew Dauter, is involved in developing new methods for phasing macromolecular structures by anomalous scattering, particularly with signals from comparatively light atoms such as bromine. This Section has also been involved in collaborative efforts with a number of groups within and outside MCL in extending the resolution of crystal structures to atomic levels. The principal interest of Dr. Xinhua Ji's Biomolecular Structure Section is the structure and function of biomolecular systems with anticancer and antimicrobial significance and structure-based drug design targeting these biomolecules. Systems under study include detoxification enzymes, folate and shikimate pathway enzymes, RNA polymerase-associated transcription factors, and RNA processing proteins.Dr. Jacek Lubkowski’s Macromolecular Assembly Structure and Cell Signaling Section is investigating structural basis of anti-viral and anti-bacterial activity of various proteins involved in intercellular signaling. Current studies involving a wide range of chemokines, defensins, and their analogs will soon be extended to chemokine receptors. The Protein Engineering Section, headed by Dr. David Waugh, focuses primarily on developing new technology for high-throughput protein expression and purification, and on the structural proteomics of virulence factors in potential agents of bioterrorism. Under the direction of Dr. Alexander Wlodawer, the Protein Structure Section has been investigating retroviral protease and integrase; lectins with antiviral activity; a variety of other proteases, ribonucleases, and kinases; and a number of cytokines and cytokine-receptor complexes.