Assessing Protein Folding and Design with the Pure Water
1,2
2
1
1
2
Jianxing Song , Minfen Li , Jingxian Liu , Xiaoyuan Ran , Miaoqing Fang ,
2
2
Jiahai Shi , Haina Qin June-Mui Goh
2
(1Department of Biochemistry, Yong Loo Lin School of Medicine and 2Department of
Biological Sciences, Faculty of Science, National University of Singapore; 10 Kent
Ridge Crescent, Singapore 119260)
One unconquerable problem encountered in experimentally studying protein
folding and design is that many protein sequences are highly buffer-insoluble. So far
there is no universe method to characterize these insoluble proteins. Recently we have
discovered that all buffer-insoluble protein in our laboratory could be solubilized in saltfree water. This discovery offered us: 1) to determine the NMR structure of insoluble
Nogo-60 and further designed Nogo-54 molecule which holds promising potential for
developing therapeutics to enhance CNS regeneration; 2) to visualize NMR structural and
dynamic properties of a denatured SH3 domain. Identification of persistent long-range
NOEs indicated that this SH3 domain owns a native-like tertiary topology although its
secondary structures become highly-distorted or/and flexible. Most importantly, our
discovery may open up an avenue to assess the relationship between protein sequence
and conformation spaces by mapping out structural properties of all intermediate
sequences, most of which are highly-insoluble.
References
1. Li M, Liu J, Song J. (2006) Nogo goes in the pure water: Solution structure of Nogo60 and design of the structured and buffer-soluble Nogo-54 for enhancing CNS
regeneration. Protein Sci. 15, 1835-41.
2. Li M et al (2006) Resurrecting Abandoned Proteins with the Pure Water: Biophys. J. in
press.