title: Studies on synthetic LuxR solo hybrids.
abstract: A sub-group of LuxR family of proteins that plays important roles in quorum sensing, a process of cell-cell communication, is widespread in proteobacteria. These proteins have a typical modular structure consisting of N-ter autoinducer binding and C-ter helix-turn-helix (HTH) DNA binding domains. The autoinducer binding domain recognizes signaling molecules which are most often N-acyl homoserine lactones (AHLs) but could also be other novel and yet unidentified molecules. In this study we carried out a series of specific domain swapping and promoter activation experiments as a first step to engineer synthetic signaling modules, taking advantage of the modularity and the versatile/diverse signal specificities of LuxR proteins. In our experiments the N-ter domains from different LuxR homologs were either interchanged or placed in tandem followed by a C-ter domain. The rational design of the hybrid proteins was supported by a structure-based homology modeling studies of three members of the LuxR family (i.e., LasR, RhlR, and OryR being chosen for their unique ligand binding specificities) and of selected chimeras. Our results reveal that these LuxR homologs were able to activate promoter elements that were not their usual targets; we also show that hybrid LuxR proteins retained the ability to recognize the signal specific for their N- ter autoinducer binding domain. However, the activity of hybrid LuxR proteins containing two AHL binding domains in tandem appears to depend on the organization and nature of the introduced domains. This study represents advances in the understanding of the modularity of LuxR proteins and provides additional possibilities to use hybrid proteins in both basic and applied synthetic biology based research.
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy ; Centro de Ciencias da Saude, Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil.
authors.forename: Daniel Passos
authors.initials: DP
authors.lastname: da Silva
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Hitendra K
authors.initials: HK
authors.lastname: Patel
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Juan F
authors.initials: JF
authors.lastname: González
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Devescovi
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Xianfa
authors.initials: X
authors.lastname: Meng
authors.affiliation: Istituto di Cristallografia, Unità Organizzativa di Supporto di Basovizza (Trieste), Consiglio Nazionale delle Ricerche Trieste, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Covaceuszach
authors.affiliation: Istituto di Cristallografia, Unità Organizzativa di Supporto di Basovizza (Trieste), Consiglio Nazionale delle Ricerche Trieste, Italy.
authors.forename: Doriano
authors.initials: D
authors.lastname: Lamba
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Subramoni
authors.affiliation: Bacteriology and Plant Bacteriology, International Centre for Genetic Engineering and Biotechnology Trieste, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Venturi
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D011994:Recombinant Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins
keywords: LuxR; LuxR solo; bacteria; lux box; quorum sensing; signaling