Abstract
Instead of a classical single-stranded deoxyribonuleic acid (DNA)-binding protein (SSB),some hyperthermophilic crenarchaea harbor a non-canonical SSB termed ThermoDBP. Two related but poorly characterized groups of proteins, which share the ThermoDBP N-terminal DNA-binding domain, have a broader phylogenetic distribution and co-exist with ThermoDBPs and/or other SSBs. We have investigated the nucleic acid binding properties and crystal structures of representatives of these groups of ThermoDBP-related proteins (ThermoDBP-RPs) 1 and 2. ThermoDBP-RP 1 and 2 oligomerize by different mechanisms and only ThermoDBP-RP2 exhibits strong single-stranded DNA affinity in vitro. A crystal structure of ThermoDBP-RP2 in complex with DNA reveals how the NTD common to ThermoDBPs and ThermoDBP-RPs can contact the nucleic acid in a manner that allows a symmetric homotetrameric protein complex to bind single-stranded DNA molecules asymmetrically. While single-stranded DNA wraps around the surface or binds along channels of previously investigated SSBs, it traverses an internal, intersubunit tunnel system of a ThermoDBP-RP2 tetramer. Our results indicate that some archaea have acquired special SSBs for genome maintenance in particularly challenging environments.
Item Type: | Journal article |
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Faculties: | Chemistry and Pharmacy > Department of Biochemistry |
Subjects: | 500 Science > 540 Chemistry |
ISSN: | 0305-1048 |
Language: | English |
Item ID: | 33854 |
Date Deposited: | 15. Feb 2017, 14:45 |
Last Modified: | 04. Nov 2020, 13:11 |