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1. Non-Additive Effects of Binding Site Mutations in Calmodulin

   https://doi.org/10.1021/acs.biochem.9b00096  

   Edington, Sean C.; Halling, D. Brent; Bennett, Suzanna M.; Middendorf, Thomas R.; Aldrich, Richard W.; Baiz, Carlos R. (June 2019, Biochemistry)
2. Computational Analysis of Binding Interactions between the Ryanodine Receptor Type 2 and Calmodulin

   https://doi.org/10.1021/acs.jpcb.1c03896  

   Greene, D’Artagnan; Barton, Michael; Luchko, Tyler; Shiferaw, Yohannes (September 2021, The Journal of Physical Chemistry B)
3. Regulation of MILDEW RESISTANCE LOCUS-O trafficking by calmodulin-binding domains

   https://doi.org/10.1093/jxb/eraf047  

   Yuan, Jing; Ogawa, Sienna_T; Jones, Daniel_S; Lucca, Noel; Ju, Yan; Kessler, Sharon_A; Murray, ed., James (February 2025, Journal of Experimental Botany)

   Abstract Flowering plant sexual reproduction relies on the communication between the pollen tube and synergid cells to induce pollen tube bursting. During this process, the MILDEW RESISTANCE LOCUS-O (MLO) protein NORTIA (NTA) is polarly trafficked from the Golgi, where it is inactive, to the filiform apparatus, where it is functional in synergids. MLOs were recently described as calcium channels and have been proposed to be negatively regulated through calmodulin (CaM) binding at a conserved C-terminal calmodulin-binding domain (CaMBD). To determine whether CaM binding is necessary for MLO function during pollen tube reception, C-terminal truncations and CaMBD point mutations were made in NTA. Point mutations were also generated in a constitutively filiform apparatus-localized chimeric NTA containing the MLO1 C-terminus. In this study, we demonstrate that mutating the MLO1 and NTA CaMBD reduces the ability for MLOs to function during pollen tube reception. This is in part due to altered subcellular localization of the CaMBD mutants in synergids. We showed that the CaMBD is not necessary for Golgi localization of MLOs, but is necessary for efficient trafficking and total protein accumulation at the filiform apparatus. Our results suggest an additional role for CaM binding as a regulator of MLO trafficking in addition to its previously proposed role as a negative regulator of MLO Ca2+ channel activity. 

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4. Dithioamide substitutions in proteins: effects on thermostability, peptide binding, and fluorescence quenching in calmodulin

   https://doi.org/10.1039/C8CC00104A  

   Walters, Christopher R.; Ferrie, John J.; Petersson, E. James (January 2018, Chemical Communications)

   Thioamide substitutions in the backbones of proteins can modulate their structure and thermostability, or serve as spectroscopic probes in fluorescence quenching experiments. Using native chemical ligation, we have produced the first examples of a protein (calmodulin) containing two thioamides. Dithioamide variants were made to explore the effects of combining stabilizing, neutral, and destabilizing single thioamide substitutions. One of the dithioamide calmodulin variants exhibited stabilization greater than any monothioamide variant, although the effect could not easily be anticipated from the results of single substitutions. Each of the calmodulin variants retained the ability to bind a target peptide, and the dithioamide proteins exhibited an increase in fluorescence quenching of tryptophan relative to their single thioamide counterparts. These results show that multiply thioamidated proteins can be synthesized, and that properly placed thioamides can be used to increase protein thermostability or enhance fluorecsence quenching in peptide binding experiments. 

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5. Identifying Key Binding Interactions Between the Cardiac L-Type Calcium Channel and Calmodulin Using Molecular Dynamics Simulations

   https://doi.org/10.1021/acs.jpcb.4c02251  

   Greene, D’Artagnan; Shiferaw, Yohannes (June 2024, The Journal of Physical Chemistry B)