March 1, 2007

Probing Proteins Can Lead To Better Understanding Of Anti-Tumor Agents

There are a number of naturally occurring chemicals that are used in phototherapy of skin diseases. Hypocrellin A (HA), which can be extracted from a parasitic fungus, has been taken orally as a folk medicine for several centuries in China. Recent studies have shown that this natural compound also displays anti-tumor and antiviral activities against several types of viruses, including human immunodeficiency virus (HIV). It is easily prepared and purified and has been intensively investigated by a broad spectrum of researchers over the past decade.

HA can photosensitize membrane proteins and lipids, damaging the membranes of tumor cells, which might cause them to die. In order to reveal the detailed photosensitive damage mechanism of HA at molecular level, researchers used a model protein with known structure, lysozyme. According to Jiahong Zhou, writing in the current issue of Spectroscopy: An International Journal, this mechanism has not been previously investigated.

Raman spectroscopy can probe the structure of biomolecules and can identify structural changes in proteins. The authors conclude that the active oxygen species released by HA induce dramatic changes in the structure of the lysozyme molecule. With more study of this mechanism, perhaps HA can serve as a therapeutic agent for a number of diseases.

The article is "Raman spectroscopic study of photosensitive damage to lysozyme structure sensitized by hypocrellin A" by J.H. Zhou, X.H. Wu, S.H. Wei, X.T. Gu, Y.Y. Feng, X.S. Wang and B.W. Zhang. The authors are from the Analysis & Testing Center, Nanjing Normal University, 210097 Nanjing, P.R. China, and the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 10010, P.R. China. It appears in Spectroscopy: An International Journal, Volume 20, Issue 5/6 (2007), published by IOS Press.

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