5ms0 | pdb_00005ms0
pseudo-atomic model of the RNA polymerase lambda-based antitermination complex solved by cryo-EM
Structural highlights
Function[RS10_ECOLI] Involved in the binding of tRNA to the ribosomes.[HAMAP-Rule:MF_00508] [NUSB_ECO45] Involved in the transcription termination process. [RPOA_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059] [NUSG_ECOLI] Participates in transcription elongation, termination and antitermination. In the absence of Rho, increases the rate of transcription elongation by the RNA polymerase (RNAP), probably by partially suppressing pausing. In the presence of Rho, modulates most Rho-dependent termination events by interacting with the RNAP to render the complex more susceptible to the termination activity of Rho. May be required to overcome a kinetic limitation of Rho to function at certain terminators. Also involved in ribosomal RNA and phage lambda N-mediated transcriptional antitermination.[1] [2] [3] [4] [5] [6] [7] [8] [9] [NUSA_ECOLI] Participates in both transcription termination and antitermination. Involved in a variety of cellular and viral termination and antitermination processes, such as Rho-dependent transcriptional termination, intrinsic termination, and phage lambda N-mediated transcriptional antitermination. Also important for coordinating the cellular responses to DNA damage by coupling the processes of nucleotide excision repair and translesion synthesis to transcription.[10] [11] [12] [13] [14] [15] [16] [17] [18] [RPOB_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01321] [RPOZ_ECOLI] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits.[HAMAP-Rule:MF_00366] [RPOC_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Publication Abstract from PubMedlambdaN-mediated processive antitermination constitutes a paradigmatic transcription regulatory event, during which phage protein lambdaN, host factors NusA, NusB, NusE and NusG, and an RNA nut site render elongating RNA polymerase termination-resistant. The structural basis of the process has so far remained elusive. Here we describe a crystal structure of a lambdaN-NusA-NusB-NusE-nut site complex and an electron cryo-microscopic structure of a complete transcription antitermination complex, comprising RNA polymerase, DNA, nut site RNA, all Nus factors and lambdaN, validated by crosslinking/mass spectrometry. Due to intrinsic disorder, lambdaN can act as a multiprotein/RNA interaction hub, which, together with nut site RNA, arranges NusA, NusB and NusE into a triangular complex. This complex docks via the NusA N-terminal domain and the lambdaN C-terminus next to the RNA exit channel on RNA polymerase. Based on the structures, comparative crosslinking analyses and structure-guided mutagenesis, we hypothesize that lambdaN mounts a multipronged strategy to reprogram the transcriptional machinery, which may include (1) the lambdaN C terminus clamping the RNA exit channel, thus stabilizing the DNA:RNA hybrid; (2) repositioning of NusA and RNAP elements, thus redirecting nascent RNA and sequestering the upstream branch of a terminator hairpin; and (3) hindering RNA engagement of termination factor rho and/or obstructing rho translocation on the transcript. Structural basis for lambdaN-dependent processive transcription antitermination.,Said N, Krupp F, Anedchenko E, Santos KF, Dybkov O, Huang YH, Lee CT, Loll B, Behrmann E, Burger J, Mielke T, Loerke J, Urlaub H, Spahn CMT, Weber G, Wahl MC Nat Microbiol. 2017 Apr 28;2:17062. doi: 10.1038/nmicrobiol.2017.62. PMID:28452979[19] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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