Article info Vol. 6  No. 4   pp.  84 ~ 91
Title Crystal structure of unphosphorylated Spo0F from Paenisporosarcina sp. TG-14, a psychrophilic bacterium isolated from an Antarctic glacier
Authors Chang Woo Lee1,2, Sun-Ha Park1, Chang Sook Jeong1,2, Chang Sup Lee3, Jong Wook Hong4,5, Hyun Ho Park6, Hyun Park1,2, HaJeung Park7* and Jun Hyuck Lee1,2*
Institutions 1Unit of Polar Genomics, Korea Polar Research Institute, Incheon 21990, Republic of Korea, 2Department of Polar Sciences, Korea University of Science and Technology, Incheon 21990, Republic of Korea, 3College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea, 4Department of Bionanotechnology, Graduate School, Hanyang University, Seoul 04763, Republic of Korea, 5Department of Bionanoengineering, Hanyang University, Kyunggi-do 15588, Republic of Korea, 6College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul 06974, Republic of Korea, 7X-Ray Core, TRI, The Scripps Research Institute, Jupiter, FL 33458, USA *Correspondence: hajpark@scripps.edu, junhyucklee@kopri.re.kr
Abstract Spo0F is a response regulator that modulates sporulation, undergoes phosphorylation for phosphorelay signal transduction, and interacts with various regulatory proteins; however, the mechanisms through which phosphorylation induces structural changes and regulates interactions with binding partners remain unclear. Here, we determined the unphosphorylated crystal structure of Spo0F from the psychrophilic bacterium Paenisporosarcina sp. TG-14 (PaSpo0F) and established a phosphorylation-state structural model. We found that PaSpo0F underwent structural changes (Lys54 and Lys102) by phosphorylation and generated new interactions (Lys102/Gln10 and Lys54/Glu84) to stabilize the β4/α4 and β1/α1 loop structures, which are important target-protein binding sites. Analysis of Bacillus subtilis Spo0 variants revealed movement by BsSpo0F Thr82 and Tyr84 residues following interaction with BsSpo0B, providing insight into the movement of corresponding residues in PaSpo0F (Thr80 and Tyr82), with further analysis of BsSpo0F/BsRapH interaction revealing alterations in the β4/α4 loop region. These results suggest that phosphorylation-induced structural rearrangement might be essential for PaSpo0F activation and expand the understanding of Spo0F-specific activation mechanisms during sporulation.