Single Molecule Detection and Manipulation.

The purpose of this program announcement is to encourage basic research on the detection and manipulation of single molecules. Recent advances in optical imaging and biomechanical techniques have shown that it is possible to make observations on the dynamic behavior of single molecules, to determine mechanisms of action at the level of an individual molecule, and to explore heterogeneity among different molecules within a population. These studies have the potential to provide fundamentally new information about biological processes and are critical for a better understanding of cellular function. Current high-resolution methods such as X-ray crystallography and NMR have provided a vast array of structural detail for biological molecules, yet the output of these methods is limited by its static molecular view and ensemble averaging. Single molecule methods provide an alternative set of approaches that will lead to a more direct view of the action of individual molecules without the need to infer process or function from static structures. Real-time measurements on the spatial and temporal fluctuations of single molecules in living cells, which are not possible using other methods, are a major goal of this initiative.

Despite the promise of single molecule methods, there are a number of technical challenges that must be met to optimize these studies. Development of the collateral chemistry and instrumentation required to carry out single molecule studies is essential for progress. New tools and strategies, as well as refinement of current methods, are also needed. Single molecule methods are likely to lead to significant advances in understanding molecular movement, dynamics, and function.

The goals of single molecule research are to observe the dynamic behavior of individual molecules, to explore heterogeneity among molecules, and to determine mechanisms of action. Single molecule studies are uniquely designed to yield information about molecular motion, behavior, and fluctuations over time and space. An important aspect of the research will be to measure features of individual molecules that are masked by ensemble measurements. Real-time observation of single molecules in live cells relative to in vitro studies is an important goal.

Potentially any biological molecule is a target for study. Typical molecules are members of multicomponent systems that change in response to environmental cues or specific cellular signals. The specific objectives of this program announcement are to 1) encourage development and extension of existing single molecule technologies to examine molecular motion, behavior, heterogeneity, and fluctuations over time and space; 2) devise new tools and strategies for studying single molecules; 3) validate the methodology used to study single molecules to establish the reliability of the observations, with differences between ensemble and single molecule measurements to be clarified so that the contributions of the single molecule to the ensemble behavior are understood; 4) encourage studies on the 3-D visualization of cellular processes in real time in the living cell at high resolution (many complex cellular processess are amenable to analysis using single molecule methods); and 5) develop the collateral chemistry to facilitate the detection and handling of target molecules. Applicants are encouraged to include physicists, engineers, and computational scientists in the strategies to solve instrumentation problems related to single molecule studies.

Applications are to be submitted on the grant application form PHS 398 (rev. 4/98) and will be accepted at the following receipt dates: 1 July 2001 and 1 November 2001. Application kits are available at most institutional offices of sponsored research and may be obtained from the Division of Extramural Outreach and Information Resources, NIH, 6701 Rockledge Drive, MSC 7910, Bethesda, MD 20892-7910 USA, 301-435-0714, e-mail: [e-mail]. Additional information is available on the Internet at http://grants.nih.gov/grants/guide/ pa-files/PA-01-049.html.

Contact: Catherine Lewis, Division of Cell Biology and Biophysics, National Institute of General Medical Sciences, Building 45, Room 2AS.13C, Bethesda, MD 20892 USA, 301-594-0828, fax: [phone], e-mail: [e-mail]; Nancy L. Freeman, National Institute on Deafness and Other Communication Disorders, Executive Plaza South, Room 400C, 6120 Executive Boulevard, MSC 7180, Rockville, MD 20852 USA, 301-402-3458, fax: [phone], e-mail: [e-mail]; Jeffery A. Schloss, Division of Extramural Research, National Human Genome Research Institute, Building 31, Room B2-B07, Bethesda, MD 20892-2033 USA, 301-496-7531, fax: [phone], e-mail: [e-mail]. Reference: PA No. PA-01-049