Mass spectrometry locates local and allosteric conformational changes that occur on cofactor binding

作者：Beveridge Rebecca; Migas Lukasz G; Payne Karl A P; Scrutton Nigel S; Leys David; Barran Perdita E

来源：Nature Communications, 2016, 7(1): 12163.

DOI：10.1038/ncomms12163

Fdc1 is a decarboxylase enzyme that requires the novel prenylated FMN cofactor for activity. Here, we use it as an exemplar system to show how native top-down and bottom-up mass spectrometry can measure the structural effect of cofactor binding by a protein. For Fdc1(Ubix), the cofactor confers structural stability to the enzyme. IM-MS shows the holo protein to exist in four closely related conformational families, the populations of which differ in the apo form; the two smaller families are more populated in the presence of the cofactor and depopulated in its absence. These findings, supported by MD simulations, indicate a more open structure for the apo form. HDX-MS reveals that while the dominant structural changes occur proximal to the cofactor-binding site, rearrangements on cofactor binding are evident throughout the protein, predominantly attributable to allosteric conformational tightening, consistent with IM-MS data.

• 出版日期2016-7