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Updated: Jul 5, 2026

Analyzing and Building Nucleic Acid Structures with 3DNA
Published on: April 26, 2013
Hexameric ring structure of the N-terminal domain of Mycobacterium tuberculosis DnaB helicase
Tapan Biswas1, Oleg V Tsodikov
1Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA.
Abstract:
Hexameric DnaB helicase unwinds the DNA double helix during replication of genetic material in bacteria. DnaB is an essential bacterial protein; therefore, it is an important potential target for antibacterial drug discovery. We report a crystal structure of the N-terminal region of DnaB from the pathogen Mycobacterium tuberculosis (MtDnaBn), determined at 2.0 A resolution. This structure provides atomic resolution details of formation of the hexameric ring of DnaB by two distinct interfaces. An extensive hydrophobic interface stabilizes a dimer of MtDnaBn by forming a four-helix bundle. The other, less extensive, interface is formed between the dimers, connecting three of them into a hexameric ring. On the basis of crystal packing interactions between MtDnaBn rings, we suggest a model of a helicase-primase complex that explains previously observed effects of DnaB mutations on DNA priming.
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