Recently, because of great advances made in X-ray protein structural analysis technique, together with the building of large-sized Synchrotron radiation systems in many parts of the world, X-ray structure analysis of the protein became so familiar to many researchers and new results are continually published. It is now possible to locate the site of the reaction process in the protein used to be considered as a black box in the function research by biochemical (enzymatic) methods in the past. Because of this, it is now a marvel that the protein function research has recently been greatly progressed by X-ray structure analysis. However, as mentioned above, for the purpose of describing (understanding) the function of the protein as a chemical reaction, X-ray analysis at higher resolution is needed.

Infrared spectrometry has been known as a method to directly measure the frequency of the chemical bond since olden days and used to be one of the important methods to determine the structure of the organic compound. However, because great advances were made in gas chromatography and quantitative analysis, infrared spectrometry is not considered as an important method for structure determination in the chemical field in recent years. Still, infrared spectrometry is considered important as a method to directly measure energy levels (chemical reactivity) in the chemical field. However, in life science field, infrared spectrometry is considered not applicable except in a special case, since inherent physiological function is greatly influenced if water, including the protein system, which gives rise to a high background, is removed. Also, there were cases in which infrared spectra of the protein solution at high concentration were taken by spectral accumulation for a long period of time at short light path, but to pursue the chemical reaction driven by the protein under such an experimental condition is hopeless. Anyhow, it is strange that to challenge the elucidation of the chemical reaction by overcoming the limitation of X-ray structure analysis has not been attempted. One of the reasons for this may be that information on the three-dimensional structure derived from X-ray structure analysis is so impressive and attractive that the viewpoint that “any physiological process is comprised of chemical reactions, each driven by proteins, after all” is forgotten. Further, vibration spectra of compounds having absorption in the visible to ultraviolet region can be measured by resonance Raman spectrometry. Therefore, it can be said that both infrared spectrometry and resonance Raman spectrometry can work in cooperation.

Picobiology is expected to cause revolutionary developments in structural biology to provide great scientific impacts on almost all of the life science fields. A contribution toward the basic science field like this will help the long-range development of every applied field. However, the above-mentioned research on high-resolution protein structure is also expected to contribute directly to the drug development.

The three-dimensional structure of the target protein for the drug is noticed by the pharmaceutical companies, as it is important information for the search of drugs that regulate the function of protein, so each pharmaceutical company started to independently tackle the crystallization and high-resolution X-ray structure analysis of each target protein. However, research at picobiology level is not planned since the high-performance infrared spectrometry system has not been developed. Consequently, the impact of picobiology on the drug development is expected to be extremely large.