title: Specificity of the E. coli LysR-type transcriptional regulators.
abstract: BACKGROUND
  Families of paralogous oligomeric proteins are common in biology. How the specificity of assembly evolves is a fundamental question of biology. The LysR-Type Transcriptional Regulators (LTTR) form perhaps the largest family of transcriptional regulators in bacteria. Because genomes often encode many LTTR family members, it is assumed that many distinct homooligomers are formed simultaneously in the same cell without interfering with each other's activities, suggesting specificity in the interactions. However, this assumption has not been systematically tested.
  
  
  RESULTS
  A negative-dominant assay with λcI repressor fusions was used to evaluate the assembly of the LTTRs in E. coli K-12. Thioredoxin (Trx)-LTTR fusions were used to challenge the homooligomeric interactions of λcI-LTTR fusions. Eight cI-LTTR fusions were challenged with twenty-eight Trx fusions. LTTRs could be divided into three classes based on their interactions with other LTTRs.
  
  
  CONCLUSIONS
  Multimerization of LTTRs in E. coli K-12 is mostly specific. However, under the conditions of the assay, many LTTRs interact with more than one noncognate partner. The physiological significance and physical basis for these interactions are not known.
authors.affiliation: Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Gwendowlyn S
authors.initials: GS
authors.lastname: Knapp
authors.forename: James C
authors.initials: JC
authors.lastname: Hu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D003433:Crosses, Genetic; D004247:DNA / Q000235:genetics; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial; D005799:Genes, Dominant; D016680:Genome, Bacterial; D008957:Models, Genetic; D016366:Open Reading Frames; D010641:Phenotype; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D013879:Thioredoxins; C073470:LysR protein, Bacteria; D004247:DNA