5h45
From Proteopedia
Crystal structure of the C-terminal Lon protease-like domain of Thermus thermophilus RadA/Sms
Structural highlights
FunctionQ5SKV2_THET8 DNA-dependent ATPase involved in processing of recombination intermediates, plays a role in repairing DNA breaks. Stimulates the branch migration of RecA-mediated strand transfer reactions, allowing the 3' invading strand to extend heteroduplex DNA faster. Binds ssDNA in the presence of ADP but not other nucleotides, has ATPase activity that is stimulated by ssDNA and various branched DNA structures, but inhibited by SSB. Does not have RecA's homology-searching function.[RuleBase:RU003555] Plays a role in repairing double-strand DNA breaks, probably involving stabilizing or processing branched DNA or blocked replication forks.[HAMAP-Rule:MF_01498] Publication Abstract from PubMedHomologous recombination (HR) plays an essential role in the maintenance of genome integrity. RecA/Rad51 paralogs have been recognized as an important factor of HR. Among them, only one bacterial RecA/Rad51 paralog, RadA, is involved in HR as an accessory factor of RecA recombinase. RadA has a unique Lon protease-like domain (LonC) at its C terminus, in addition to a RecA-like ATPase domain. Unlike Lon protease, RadA's LonC domain does not show protease activity but is still essential for RadA-mediated DNA repair. Reconciling these two facts has been difficult because RadA's tertiary structure and molecular function are unknown. Here, we describe the hexameric ring structure of RadA's LonC domain, as determined by X-ray crystallography. The structure revealed the two positively charged regions unique to the LonC domain of RadA are located at the intersubunit cleft and the central hole of a hexameric ring. Surprisingly, a functional domain analysis demonstrated the LonC domain of RadA binds DNA, with site-directed mutagenesis showing that the two positively charged regions are critical for this DNA-binding activity. Interestingly, only the intersubunit cleft was required for the DNA-dependent stimulation of ATPase activity of RadA, and at least the central hole was essential for DNA repair function. Our data provide the structural and functional features of the LonC domain and their function in RadA-mediated DNA repair. The Lon protease-like domain in the bacterial RecA paralog RadA is required for DNA binding and repair.,Inoue M, Fukui K, Fujii Y, Nakagawa N, Yano T, Kuramitsu S, Masui R J Biol Chem. 2017 Jun 9;292(23):9801-9814. doi: 10.1074/jbc.M116.770180. Epub, 2017 Apr 21. PMID:28432121[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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