The Crystal Structure of Bacillus subtilis YycI Reveals a Common Fold for Two Members of an Unusual Class of Sensor Histidine Kinase Regulatory Proteins

Abstract

YycI and YycH are two membrane-anchored periplasmic proteins that regulate the essential Bacillus subtilis YycG histidine kinase through direct interaction. Here we present the crystal structure of YycI at a 2.9-Å resolution. YycI forms a dimer, and remarkably the structure resembles that of the two C-terminal domains of YycH despite nearly undetectable sequence homology (10%) between the two proteins.