Date of Submission
Chemistry and Biochemistry
Project Advisor 1
During times of low nitrogen, heterocyst differentiation in the cyanobacteria Anabaena sp. strain PCC 7120 happens at constant intervals; this is helped set in motion by the DNA-binding autoinducer protein HetR, which is inhibited by the pentapeptide RGSGR strand of the PatS protein. Past research has explored whether replacements or addition of amino acids in the PatS pentapeptide chain have enhanced or lowered the binding affinity of HetR to its target DNA substrate, which this project aims to be a continuation of. We have transformed chemically competent BL21(DE3) E. coli to produce HetR protein, which we then purified, and have tested the binding affinity of different PatS peptides to HetR using isothermal titration calorimetry (ITC) and electrophoretic mobility shift assays (EMSA). Current results show the results of the HetR purification process and the binding assays from EMSA, as well as reaction saturation curves from ITC, in which PatS-6 (ERGSAR) proves to have a stronger affinity to HetR than the wildtype pentapeptide. Further work would focus on increasing the yield from the HetR purification process and to discern the binding affinities of other PatS mutations.
Open Access Agreement
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Ricarte, Elan Emmanuelle Infante, "The Effects of PatS Peptide Mutations on HetR Protein Binding to DNA" (2023). Senior Projects Spring 2023. 28.
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