PEP-19 is a small, intrinsically disordered protein found primarily in the Purkinje cells of the cerebellum. PEP-19’s only known function is to regulate calcium binding to the protein calmodulin (CaM), and it does this by binding CaM, which in turn calmodulin’s calcium binding kinetics. Upon CaM binding, Pep-19 develops α-helical structure. CaM binds to over 300 known targets, with most of these interactions taking place when CaM is bound to calcium, making PEP-19’s regulatory function critical to biological processes.. Despite being intrinsically disordered PEP-19 has been shown to weakly bind calcium ions even in the absence of CaM, possibly contributing to its ability to protect against calcium fluctuations. Pep-19 has also been known to counteract the progression of several disorders, including Alzheimer’s disease and Downs syndrome, because of its ability to regulate calcium sensing when bound to CaM. We utilized fluorimetry to investigate possible differences in the conformational ensemble of PEP-19, in the presence and absence of calcium. Upon addition of calcium, FRET and anisotropy measurements indicate that calcium does slightly alter the conformational ensemble of PEP-19.

Altering the conformational ensemble of Pep-19 using calcium

253rd National Meeting (2017)

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