120th General Meeting of the KCS

Type Award Lecture in Division
Area Frontiers in Chemical Biology & Protein Chemistry
Room No. Room C311+C312
Time FRI 10:15-:
Code BIO-4
Subject Structural studies on protein complexes from bacteriophage, flagellum, and divisome
Authors Hyung Ho Lee
Division of Chemistry, Seoul National University, Korea
Abstract Atomic structure on protein complexes is crucial for understanding its molecular mechanism. In this talk, I will present structural and functional studies on three protein complexes. In the first part, the structural and functional studies on repressor-antirepressor complex from bacteriophage will be discussed. We showed an uncharacterized mechanism of non-canonical DNA binding and induction by a repressor (Rep) from the temperate Salmonella phage SPC32H; this mechanism was revealed using the crystal structures of homotetrameric Rep (92-198) and a hetero-octameric complex between the Rep and its antirepressor (Ant). The canonical method of inactivating a repressor is through the competitive binding of the antirepressor to the operator-binding site of the repressor; however, these studies revealed several non-canonical features. In the second part, the structural and functional studies on the FliD-FliT complex from Salmonella will be discussed. Bacterial flagellar biogenesis is controlled by a negative feedback loop. When FliD was secreted at the late step of flagellar assembly, the FliD-FliT complex disassembled and free FliT bound to the FlhDC complex, a master regulator of flagellar biogenesis, subsequently inhibiting the overall expression of flagellar proteins. In this study, we analyzed the role of the FliD C-terminal domain in pentamer formation and interaction with FliT. In the third part, the structural and functional studies on the component proteins of divisome will be discussed.
E-mail hyungholee@snu.ac.kr