Characterizing the interaction of the Bacillus subtilis ClpC chaperone with a novel sporulation adaptor protein
Date
2023-06-28
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Abstract
Protein degradation is a complex process that affects biological pathways. Proteolysis in all organisms is carried out by the ATP-dependent AAA+ proteases, including in the bacterium Bacillus subtilis, which undergoes sporulation, resulting in the formation of a metabolically dormant cell type called a spore. The molecular mechanisms that drive metabolic dormancy are poorly understood, but research suggests that this may involve the degradation of key metabolic enzymes in the forespore. Previous lab members have identified an uncharacterized gene micA expressed in the developing spore; its knockout displays phenotypes consistent with increased metabolic capacity. Our model suggests MicA functions as an adaptor protein, recruiting key metabolic enzymes to the chaperone-protease, ClpCP for degradation. MicA interacts with an interface of the ClpC N-domain at 3 different electrostatic sites confirmed by a co-crystal structure. In this project, we hypothesize that the lysine at position 12 (K12) of ClpC is important for the interaction of MicA with ClpC. Alteration of ClpC K12 did not disrupt overall ClpC function, but rather specifically blocked the toxicity of micA during vegetative growth and, like a mutant lacking micA, caused increased gene expression in the developing spore. Therefore, the K12 site on the ClpC protein is necessary for MicA and ClpC interaction.
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Biology, Microbiology, Bacteria, Bacillus subtilis