To test the existence of the salt bridge and stability of the HIV-1 p17 matrix protein. an E12A (mutated at helix 1) was established to abolish possible electrostatic interactions. The chemical shift perturbation from the comparison between wild type and E12A suggested the existence of an electrostatic interaction in wild type between E12 and H89 (located in helix 4). Unexpectedly. https://ashleyshomestores.shop/product-category/table-clock-set-of-2/