Dedicated Life Scientist with experience in laboratory research. Expertise in data analysis and background in biochemistry and molecular and cellular biology. Proficient in conducting laboratory experiments while mentoring on research methods and data collection procedures. Hardworking and driven with organizational and analytical skills combined with unparalleled dedication to research excellence. Passionate about increasing knowledge to drive scientific growth. Ready to apply knowledge and 10 years of experience in research.
Advisor: Dr. Peter Chien
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American Society for Biochemistry and Molecular Biology Annual Meeting, Seattle WA, 2023
Journal of Biological Chemistry
The ATPase Associated with diverse cellular Activities (AAA+) family of proteases, particularly Lon, plays a crucial role in cellular proteolysis and stress responses. The regulation of Lon is essential for maintaining protein quality control in the cell. In this study, we investigated the impact of DNA binding on Lon's biochemical activity using Caulobacter crescentus as a model system. Our results reveal that while Lon can bind both double-stranded (ds)DNA and single-stranded (ss)DNA, only ssDNA binding induces changes in Lon's biochemical activity. Upon ssDNA binding, Lon's ATP hydrolysis increases, leading to enhanced degradation of protein substrates, including physiologically important targets. We demonstrate that mutations in basic residues crucial for DNA binding result in loss of ssDNA binding, with charge-specific consequences. Mutating these residues to negatively charged glutamates induces activation like ssDNA binding, while neutralizing the charge compromises Lon's activity. Further investigation indicates that ssDNA binding increases Lon's affinity for ATP, affecting both ATP hydrolysis and proteolysis. The Lon4E mutant, mimicking a DNA-bound state with negative charges, exhibits increased catalytic activity. Additionally, Lon4E is less inhibited by ADP, supporting the idea that changes in surface electrostatics activate Lon. In contrast, the Lon4A mutant, lacking negative charges, is less active, emphasizing the role of charge accumulation in Lon's function. This study provides insights into the complex regulation of Lon protease by DNA binding, highlighting the importance of surface electrostatics in modulating Lon's enzymatic activity.