Enhancement of DNA flexibility in vitro and in vivo by HMGB box A proteins carrying box B residues

Nadia T. Sebastian, Emily M. Bystry, Nicole A. Becker, L James Maher III

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

HMGB proteins are abundant non-histone components of eukaryotic chromatin. The biological function of DNA sequence-nonspecific HMGB proteins is obscure. These proteins are composed of one or two conserved HMG box domains, each forming three R-helices that fold into a sequence-nonspecific DNA-binding module recognizing the DNA minor groove. Box A and box B homology domains have subtle sequence differences such that box B domains bend DNA strongly while DNA bending by isolated box A domains is weaker. Both box A and box B domains preferentially bind to distorted DNA structures. Here we show using DNA cyclization kinetics assays in vitro and Escherichia coli DNA looping assays in vivo that an isolated HMG box A domain derived from human HMGB2 folds poorly and does not enhance apparent DNA flexibility. Surprisingly, substitution of a small number of cationic residues from the N-terminal leader of a functional yeast box B protein, Nhp6Ap, confers the ability to enhance DNA flexibility. These results demonstrate important roles for cationic leader amino acids in HMGB folding, DNA interaction, and DNA bending.

Original languageEnglish (US)
Pages (from-to)2125-2134
Number of pages10
JournalBiochemistry
Volume48
Issue number10
DOIs
StatePublished - Mar 17 2009

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HMGB Proteins
DNA
Proteins
HMG-Box Domains
DNA sequences
Assays
HMGB2 Protein
In Vitro Techniques
Cyclization
Yeast
Escherichia coli
Chromatin

ASJC Scopus subject areas

  • Biochemistry

Cite this

Enhancement of DNA flexibility in vitro and in vivo by HMGB box A proteins carrying box B residues. / Sebastian, Nadia T.; Bystry, Emily M.; Becker, Nicole A.; Maher III, L James.

In: Biochemistry, Vol. 48, No. 10, 17.03.2009, p. 2125-2134.

Research output: Contribution to journalArticle

Sebastian, Nadia T. ; Bystry, Emily M. ; Becker, Nicole A. ; Maher III, L James. / Enhancement of DNA flexibility in vitro and in vivo by HMGB box A proteins carrying box B residues. In: Biochemistry. 2009 ; Vol. 48, No. 10. pp. 2125-2134.
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