EF-hand calcium sensors respond structurally to changes in intracellular Ca2+ concentration, triggering diverse cellular responses and resulting in broad interactomes. Despite impressive advances in decoding their structure-function relationships, the folding mechanism of neuronal calcium sensors is still elusive. We used single-molecule optical tweezers to study the folding mechanism of the human neuronal calcium sensor 1 (NCS1). Two intermediate structures induced by Ca2+ binding to the EF-hands were observed during refolding. The complete folding of the C domain is obligatory for the folding of the N domain, showing striking interdomain dependence. Molecular dynamics results reveal the atomistic details of the unfolding process and rationalize the different domain stabilities during mechanical unfolding. Through constant-force experiments and hidden Markov model analysis, the free energy landscape of the protein was reconstructed. Our results emphasize that NCS1 has evolved a remarkable complex interdomain cooperativity and a fundamentally different folding mechanism compared to structurally related proteins. © 2013 Elsevier Ltd.
Single-molecule folding mechanism of an EF-hand neuronal calcium sensor / Heidarsson P.O.; Otazo M.R.; Bellucci L.; Mossa A.; Imparato A.; Paci E.; Corni S.; Di Felice R.; Kragelund B.B.; Cecconi C.. - In: STRUCTURE. - ISSN 0969-2126. - STAMPA. - 21:10(2013), pp. 1812-1821. [10.1016/j.str.2013.07.022]
Single-molecule folding mechanism of an EF-hand neuronal calcium sensor
Paci E.;
2013
Abstract
EF-hand calcium sensors respond structurally to changes in intracellular Ca2+ concentration, triggering diverse cellular responses and resulting in broad interactomes. Despite impressive advances in decoding their structure-function relationships, the folding mechanism of neuronal calcium sensors is still elusive. We used single-molecule optical tweezers to study the folding mechanism of the human neuronal calcium sensor 1 (NCS1). Two intermediate structures induced by Ca2+ binding to the EF-hands were observed during refolding. The complete folding of the C domain is obligatory for the folding of the N domain, showing striking interdomain dependence. Molecular dynamics results reveal the atomistic details of the unfolding process and rationalize the different domain stabilities during mechanical unfolding. Through constant-force experiments and hidden Markov model analysis, the free energy landscape of the protein was reconstructed. Our results emphasize that NCS1 has evolved a remarkable complex interdomain cooperativity and a fundamentally different folding mechanism compared to structurally related proteins. © 2013 Elsevier Ltd.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
