specificity of the e. coli lysr-type transcriptional regulators大肠杆菌的特异性lysr-type转录监管机构.pdf

Specificity of the E. coli LysR-Type Transcriptional Regulators Gwendowlyn S. Knapp1¤, James C. Hu1,2* 1 Department of Biochemistry and Biophysics, Texas AM University, College Station, Texas, United States of America, 2 Texas AgriLife Research, Texas AM University, College Station, Texas, United States of America 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. Methodology/Principal Findings: A negative-dominant assay with lcI 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 lcI- 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/Significance: 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. Citation: Knapp GS, Hu JC (2010) Specificity of the E. coli LysR-Type Transcriptional Regulators. PLoS ONE 5(12): e15189. doi:10.1371/journal.pone.0015189 Editor: Christophe Herman, Baylor College of Medicine, United States of America Received August 4,