Direct demodulation method for heavy atom position determination in protein crystallography  

作　　者：周亮 刘忠川 刘鹏 董宇辉 

机构地区：[1]Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciences

出　　处：《Chinese Physics C》2013年第1期133-137,共5页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(10979005);National Basic Research Program of China(2009CB918600)

摘　　要：The first step of phasing in any de novo protein structure determination using isomorphous replacement （IR） or anomalous scattering （AD） experiments is to find heavy atom positions. Traditionally, heavy atom positions can be solved by inspecting the difference Patterson maps. Due to the weak signals in isomorphous or anomalous differences and the noisy background in the Patterson map, the search for heavy atoms may become difficult. Here, the direct demodulation （DD） method is applied to the difference Patterson maps to reduce the noisy backgrounds and sharpen the signal peaks. The real space Patterson search by using these optimized maps can locate the heavy atom positions more accurately. It is anticipated that the direct demodulation method can assist in heavy atom position determination and facilitate the de novo structure determination of proteins.The first step of phasing in any de novo protein structure determination using isomorphous replacement （IR） or anomalous scattering （AD） experiments is to find heavy atom positions. Traditionally, heavy atom positions can be solved by inspecting the difference Patterson maps. Due to the weak signals in isomorphous or anomalous differences and the noisy background in the Patterson map, the search for heavy atoms may become difficult. Here, the direct demodulation （DD） method is applied to the difference Patterson maps to reduce the noisy backgrounds and sharpen the signal peaks. The real space Patterson search by using these optimized maps can locate the heavy atom positions more accurately. It is anticipated that the direct demodulation method can assist in heavy atom position determination and facilitate the de novo structure determination of proteins.

关 键 词：direct demodulation method heavy atom sites difference Patterson map protein crystallography 

分 类 号：O629.73[理学—有机化学]