title: The unphosphorylated form of the PilR two-component system regulates pilA gene expression in Geobacter sulfurreducens.
abstract: In Geobacter sulfurreducens, metal reduction and generation of bioelectricity require the participation of several elements, and among them, the type IV pili has an essential role. The pilus is composed of multiple PilA monomers. Expression of pilA gene depends mainly on the σ54 factor and the response regulator protein PilR. In this work, we characterized the role of the PilS-PilR two-component system in the regulation of the pilA gene expression. Experimental evidence indicates that PilS is autophosphorylated at the His-334 residue, which in turn is transferred to the conserved Asp-53 in PilR. Contrary to other PilS-PilR systems, substitution D53N in PilR resulted in higher activation of the pilA gene. By using a pilA::luxCDABE fusion with different promoter fragments and in vitro DNA-binding assays, we demonstrated the existence of multiple functional PilR binding sites. A regulatory model in which the non-phosphorylated PilR protein directs activation of pilA expression by binding to two sites in the promoter region of this gene is presented.
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, Cuernavaca, Morelos, 62210, México.|CONACYT-Research Fellow, Ciudad de México, México.
authors.forename: Alberto
authors.initials: A
authors.lastname: Hernández-Eligio
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, Cuernavaca, Morelos, 62210, México.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Andrade
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, Cuernavaca, Morelos, 62210, México.
authors.forename: Lizeth
authors.initials: L
authors.lastname: Soto
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, Cuernavaca, Morelos, 62210, México.|Instituto Nacional de Medicina Genómica, Periférico Sur 4809, Arenal Tepepan, Tlalpan, Ciudad de México, D.F., 14610, México.
authors.forename: Enrique
authors.initials: E
authors.lastname: Morett
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001. Col. Chamilpa, Cuernavaca, Morelos, 62210, México. katy@ibt.unam.mx.
authors.forename: Katy
authors.initials: K
authors.lastname: Juárez
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D045302:Geobacter / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; C080687:pilS protein, Bacteria
keywords: Electron transfer; Phosphorelay; Pili; Transcriptional regulator; Two-component system; pilA