LASER RAMAN PROBE OF MOLECULAR STRUCTURE IN LIVING CELLS

提出了建立一种激光拉曼显微镜的设想

It is proposed to build a laser Raman microscope which is capable of observing chromosomal material with about one micron resolution. Using this apparatus Raman spectra will be taken of chromosomes from a variety of easily available sources. By focusing a laser beam of about 1 micron or less on various portions of the chromosome and associated cellular apparatus and capturing the Raman light which is back scattered through the microscope objective, it is proposed to obtain both the classical and the resonance Raman spectra of the various chromosomal components including both protein and DNA. In particular the Raman marker band characteristic of the A, B, C, and Z forms of DNA as well as Raman bands sensitive to protein secondary structure will be sought. The presence of the Z marker bands in a portions of a gene would give evidence for the Z form. Polytene chromosomes will be examined in fixed and non-fixed states. The Raman spectra of polytene chromosomes containing bound antibodies to Z-DNA will also be taken to see if evidence can be found for presence of the Z-conformation in the DNA of polytene chromosomes upon antibody binding. This approach could settle the questions of whether or not Z-DNA exists in polytene chromosomes or whether or not antibodies are capable of pulling the DNA into the Z form upon binding. By collecting instanteous Raman spectra of the cellular components of living cells, it is proposed to determine the type, extent of and duration of conformational changes in the DNA and associated proteins during cell division. Thus, it is hoped to answer the questions as to whether Z-DNA is a naturallly occurring structure in genetic material. It is also hoped to improve the understanding of the molecular basis of the hereditary process. Such understanding can only help to formulate a more rational approach to the development of drug therapy for treatment of diseases which involve malfunction of the genetic material.