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Rearranging RNA structures at 75°C? toward the molecular mechanism and physiological function of the thermus thermophilus DEAD‐box helicase hera
Author(s) -
Klostermeier Dagmar
Publication year - 2013
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.22316
Subject(s) - thermus thermophilus , helicase , rna helicase a , hera , rna , chemistry , dead box , physics , biochemistry , escherichia coli , gene , particle physics , quantum chromodynamics
DEAD‐box helicases catalyze the ATP‐dependent destabilization of RNA duplexes. Hera is a DEAD‐box helicase from Thermus thermophilus that consists of a helicase core, followed by a C‐terminal extension comprising a dimerization domain and an RNA‐binding domain. The combined structural information on individual Hera domains provides a molecular model of the Hera dimer. The modular architecture with flexible connections between individual domains affords different relative orientations of the RBD relative to the Hera helicase core, and of the two helicase cores within the dimer. Presumably, domain movements are intimately linked to RNA binding, to the interplay of the RBD and the helicase core, and to RNA unwinding, and may impact on the functional cooperation of the two helicase cores in RNA unwinding. The in vivo function of Hera is unknown. The Hera RBD recognizes two distinct elements in the RNA substrate, a single‐stranded and a structured region. The helicase core then unwinds an adjacent RNA duplex in an ATP‐dependent reaction. Overall, this mode of action is reminiscent of DEAD‐box proteins that act as general RNA chaperones. This review summarizes the current knowledge on Hera structure and function, and discusses a possible role of Hera in the Thermus thermophilus cold‐shock response. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 1137–1146, 2013.