http://reply.papertrans.cn/1/4/308/308-31.png
Submitted on: 10 September 2002.
Revised on: 06 December 2002.
Accepted on: 22 December 2002.
___________________Acta Crystallographica Section D-Structural Biology
http://reply.papertrans.cn/1/4/308/308-33.png
http://reply.papertrans.cn/1/4/308/308-34.png
http://reply.papertrans.cn/1/4/308/308-35.png
http://reply.papertrans.cn/1/4/308/308-36.png