How Proteins Pack into Crystals: Nuclei Achieve Translation Symmetries by Growing

Dan Feng^* and Zong-Hao Zeng

Center of Molecular Biology, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China; E-mail: fengdan_bj@hotmail.com

^* To whom correspondence should be addressed.

Received October 1, 2003; Revision received November 5, 2003

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How protein molecules pack into a crystal remains problematic. Packing units are direct materials for packing into crystals. The group generator method is introduced for automatically identifying the packing unit. By introducing deviations into the nucleation stage of crystallization, we proved that these deviations diminish in further packing. This process illustrates how translation symmetries are achieved by the growing of nuclei. Two effects, the size effect and the close up effect, are found to behave differently in this process.

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KEY WORDS: crystal packing, frustration, packing unit, nucleation, group generator method

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