Editing Rho factor (section)

{{Short description|Prokaryotic protein}}
{{Infobox nonhuman protein
|image=PDB 1pv4 EBI.jpg|caption=Rho factor homohexamer
|UniProt=P0AG30|Symbol=rho
|Name=Transcription termination factor Rho
|Organism=E. coli
}}
{{Infobox protein family
|Name=Transcription termination factor Rho
|Symbol=Term_rho
|InterPro=IPR004665
}}
A '''ρ factor''' ('''Rho factor''') is a [[bacterial]] [[protein]] involved in the [[termination factor|termination]] of [[Transcription (genetics)|transcription]].<ref name="pmid33243850">{{cite journal | vauthors = Said N, Hilal T, Sunday ND, Khatri A, Bürger J, Mielke T, Belogurov GA, Loll B, Sen R, Artsimovitch I, Wahl MC | display-authors = 6 | title = Steps toward translocation-independent RNA polymerase inactivation by terminator ATPase ρ | journal = Science | volume = 371 | issue = 6524 | date = January 2021 | pmid = 33243850 | doi = 10.1126/science.abd1673 | pmc = 7864586 | hdl = 21.11116/0000-0007-AD1D-7 | hdl-access = free }}
* {{cite web |author=Emily Caldwell |date=November 26, 2020 |title=Study revealing the secret behind a key cellular process refutes biology textbooks |website=Phys.org |url=https://phys.org/news/2020-11-revealing-secret-key-cellular-refutes.html}}</ref> Rho factor binds to the transcription terminator pause site, an exposed region of single stranded RNA (a stretch of 72 nucleotides) after the [[open reading frame]] at C-rich/G-poor sequences that lack obvious secondary structure.<ref name="foster">{{cite book | vauthors = Slonczewski J, Foster JW | title = Microbiology: An Evolving Science | location = New York | publisher = W.W. Norton &, Incorporated | date = 2009 | isbn = 978-0-393-11332-7 }}</ref>

Rho factor is an essential transcription protein in bacteria.<ref>{{cite journal | vauthors = Pradeepkiran JA, Kumar KK, Kumar YN, Bhaskar M | title = Modeling, molecular dynamics, and docking assessment of transcription factor rho: a potential drug target in Brucella melitensis 16M | journal = Drug Design, Development and Therapy | volume = 9 | pages = 1897–912 | date = 2015 | pmid = 25848225 | pmc = 4386771 | doi = 10.2147/DDDT.S77020 | doi-access = free }}</ref> In ''[[Escherichia coli]]'', it is a ~274.6 kD hexamer of identical subunits. Each subunit has an RNA-binding domain and an [[adenosine triphosphate|ATP]]-[[hydrolysis]] domain. Rho is a member of the RecA/SF5 family of ATP-dependent hexameric [[helicase]]s that function by wrapping nucleic acids around a single cleft extending around the entire hexamer. Rho functions as an ancillary factor for [[RNA polymerase]].

There are two types of transcriptional termination in bacteria, rho-dependent termination and [[intrinsic termination]] (also called Rho-independent termination). Rho-dependent terminators account for about half of the ''E. coli'' factor-dependent terminators. Other termination factors discovered in ''E. coli'' include [[Replication terminator Tus family|Tau/Ter/Tus]] and nusA. Rho-dependent terminators were first discovered in [[bacteriophage]] genomes.