Upgrade of In-house X-ray Diffraction Equipment

Johns Hopkins University, Baltimore MD

Investigators

Abstract

[unreadable] DESCRIPTION (provided by applicant): Three groups in the Department of Biophysics & Biophysical Chemistry at the Johns Hopkins University School of Medicine (JHUSOM) use X-ray diffraction as a primary research tool (Amzel, mechanism of oxidoreductases, phosphoryl transfer reactions, and macromolecular recognition; Leahy, signal transduction; Wolberger, regulation of gene expression), and each of these groups collaborates with multiple groups at Hopkins as well as outside institutions. In the past several years two groups in the Department of Pharmacology at Hopkins (Cole, chemical approaches to signal transduction and gene expression; Stivers, nucleic acid metabolism) have started to use diffraction methods as a significant component of their research. These efforts began as collaborations with structural biologists at Hopkins and elsewhere but are expanding so that X-ray structure determinations are becoming a component of their independent research efforts. The current X-ray diffraction facilities at JHUSOM are heavily oversubscribed, and we propose to take advantage of recent and impressive advances in in-house X-ray generators to increase the capacity and capabilities of this facility. Specifically, we propose to acquire a Rigaku 007HF high-flux X-ray generator equipped with two sets of VariMax HF optics, one for each port on the 007HF generator. We also propose to acquire an R-axis IV++ Image Plate detector to replace an outmoded and unsupported R-axis II detector. An existing R-axis IV detector and two X-stream cryo-cooling systems will be transferred to the new generator along with the R-axis IV++ to create two high-flux X-ray stations for macromolecular crystallography. Based on test crystal comparisons and published specifications, we expect the new generator and optics to result in a 10-fold decrease in average data collection times and a substantial increase in project throughput. Owing to the decreased beam size produced by the new generator (70 5M diameter) vs. the existing equipment (300 5M diameter) and increased X-ray beam intensity, the new setup will be especially advantageous for data collection from small crystals, which make up the majority of current experiments. By increasing throughput and expanding the range of projects for which usable diffraction data can be obtained, the upgraded facility will significantly enhance a broad range of NIH-funded, health-related projects with implications for signaling, gene expression, enzyme mechanism, and drug design. [unreadable] [unreadable] [unreadable]