We propose to purchase two x-ray diffractometers that will immediately and significantly enhance the capacity of the University of Texas at El Paso to conduct biomedical research at the highest level. Specifically we will obtain both a protein crystal diffractometer and a single crystal diffractometer. The former instrumentation will be used as a core facility that will be of major benefit to the SCORE-supported subprojects of Professors Eppie Rael and Jorge Gardea-Torresdey and the latter, also a core facility will primarily be used, within the SCORE program, by the sub-project of Professor Keith H. Pannell. Furthermore, these instruments will form the equipment basis of a proposed Institute of Health Related Structural Biochemistry at U. T. El Paso under the umbrella of the Border Biomedical research Center. The research program of Dr. Rael involves the isolation of potential anti-cancer proteins from rattlesnake venom where structure/reactivity is essential; the project of Dr. Gardea seeks to uncover and understand the mechanisms of proteins involved in plant metal uptake from health-threatening soils; and the program of Dr.Pannell aims at the synthesis of structurally characterized organotin biocides with specific targets and activities. All three projects have the common denominator of needing precise structural information to understand the activity of the respective research goals. The institutional support from the U. T. El Paso administration includes the provision of $490,000 matching funds; PLUS the commitment to hire a new tenure track faculty protein crystallographer, who will be "onboard" by Fall 2002; PLUS the upgrading of the 50% staff post of Dr. Francisco Cervantes, our staff crystallographer, to a 100% post; PLUS in-kind support to modify existing space to install the new instrumentation, cost ~ $100,000- 200,000; PLUS purchase of the needed service contracts for the new instrumentation.