Interactions between HMG boxes

Susann Taudte, Hong Xin, Anthony J. Bell, Neville R. Kallenbach

Research output: Contribution to journalArticlepeer-review


Many proteins consist of subdomains that can fold and function independently. We investigate here the interaction between the two high mobility group (HMG) box subdomains of the nuclear protein rHMG1. An HMG box is a conserved amino acid sequence of approximately 80 amino acids rich in basic, aromatic and proline side chains that is active in binding DNA in a sequence or structure-specific manner. In the case of HMG1, each box can bind structural DNA substrates including four-way junctions (4WJs) and branched or kinked DNA duplexes. Since proteins containing up to six HMG boxes are known, the question arises whether linking subdomains together influences the folding or function of individual boxes. In an effort to understand interactions between individual DNA-binding domains in HMG1, we created new fusion proteins: one is an inversion of the order of the AB di-domain in HMG1 (BA); in the second, we added a third A domain C-terminal to the AB di-domain (ABA). Pairs of boxes, AB or BA, behave similarly and are functionally active. By contrast, the ABA triple subdomain construct is partially unfolded and is less active than individual boxes or di-domains. Thus, long-range interdomain effects can influence the activity of HMG boxes.

Original languageEnglish (US)
Pages (from-to)1015-1023
Number of pages9
JournalProtein Engineering
Issue number12
StatePublished - 2001


  • Circular dichroism
  • DNA binding
  • High mobility group protein 1
  • Protein stability
  • Subdomain shuffling

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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