A COMPUTER-CONTROLLED MICROSCOPY SYSTEM FOR FOLLOWING PROTEIN CRYSTAL-FACE GROWTH-RATES

A computer-controlled microscopy system for following the face growth of multiple small (approximately 10 to 50 mum) crystals during one exp erimental run is described. The major system components are a controll ing PC with a digital oscilloscope board, PC-controlled translation st ages for X, Y, and Z axes of motion, a video microscopy system, and a circuit to trigger digitization of preselected video lines. Crystal lo cations in the growth chamber are stored in an array, and sequentially accessed during each measurement cycle. Operator-selected horizontal video scan lines are digitized and these data are used to calculate th e distance between parallel faces of the crystals. The system was asse mbled from readily available components, and can be easily modified fo r other microscopy-based tracking and measuring functions.