Important roles of the conserved linker-KKS in human neuronal growth inhibitory factor

Zhi-Chun Ding, Xin Chen Teng, Qi Zheng, Feng Yun Ni, Bin Cai, Yang Wang, Guo Ming Zhou, Hong Zhe Sun, Xiang Shi Tan, Zhong Xian Huang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Metallothinein-3 (MT3), also named neuronal growth inhibitory factor (GIF), is attractive by its distinct neuronal growth inhibitory activity, which is not shared by other MT isoforms. The polypeptide chain of GIF is folded into two individual domains, which are connected by a highly conserved linker, KKS. In order to figure out the significance of the conserved segment, we constructed several mutants of human GIF (hGIF), including the K31/32A mutant, the K31/32E mutant and the KKS-SP mutant by site-directed mutagenesis. pH titration and DTNB reaction exhibited that all the three mutations made the β-domain lower in stability and looser. More significantly, change of KKS to SP also altered the general backbone conformation and metal-thiolate cluster geometry. Notably, bioassay results showed that the bioactivity of the K31/32A mutant and the K31/32E mutant decreased obviously, while the KKS-SP mutant lost inhibitory activity completely. Based on these results, we proposed that the KKS linker was a crucial factor in modulating the stability and the solvent accessibility of the Cd3S9 cluster in the β-domain through domain-domain interactions, thus was indispensable to the biological activity of hGIF.

Original languageEnglish (US)
Pages (from-to)817-826
Number of pages10
Issue number5
StatePublished - Oct 2009


  • Cell culture
  • Linker
  • Metallothionein
  • Mutation
  • Neuronal growth inhibitory factor

ASJC Scopus subject areas

  • Biomaterials
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • Metals and Alloys


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