Geschichte der Physiologie. Rothschuh, K. E.

Impact of charge state on 193 nm ultraviolet photodissociation of protein complexes

“…[10][11][12] With only ~14% of proteins functioning as monomers, understanding the networks of noncovalent interactions that create the protein architectures and stabilize protein assemblies is crucial to providing insight into molecular processes. 13 To that end, ESI-MS along with various activation methods have been employed to probe the stability, 5,[14][15][16][17][18] assembly and unfolding, 15,17,[19][20][21] topology, [15][16][17]22 and primary sequence 18,[21][22][23][24] of multimeric proteins.…”

“…Collisional activation of protein complexes is believed to be dominated by a mechanism in which typically a single subunit unfolds, causing Coulombically-favored charge redistribution; this process results in release of highly-charged, unfolded monomers from the "charged-stripped" (n-1)mers. [14][15][16]19,20,25,26 Relative stabilities of protein complexes ranging from dimers to 24-mers have been determined by monitoring dissociation profiles into monomers and subcomplexes. 14,15 Obtaining deeper structural information is limited by the asymmetric dissociation mechanism of unfolding of one subunit at a time with concomitant asymmetric charge re-distribution; however, "atypical" CID of multimers into more symmetric subcomplexes is possible depending on charge density and subunit interfacial strength.…”

“…14,15 Obtaining deeper structural information is limited by the asymmetric dissociation mechanism of unfolding of one subunit at a time with concomitant asymmetric charge re-distribution; however, "atypical" CID of multimers into more symmetric subcomplexes is possible depending on charge density and subunit interfacial strength. 15,20 Robinson and coworkers have manipulated the charge states of protein complexes via strategic use of solution additives, thus allowing the detailed examination of the impact of charge state on the dissociation of protein complexes. 14,15,19,20 Reducing the charge state mitigates extensive unfolding of the protein complexes (as observed from ion mobility data) and suppresses dissociation of the complexes, likely owing to the increased energy barrier of activation caused by decreased Coulombic repulsion.…”

“…15,20 Robinson and coworkers have manipulated the charge states of protein complexes via strategic use of solution additives, thus allowing the detailed examination of the impact of charge state on the dissociation of protein complexes. 14,15,19,20 Reducing the charge state mitigates extensive unfolding of the protein complexes (as observed from ion mobility data) and suppresses dissociation of the complexes, likely owing to the increased energy barrier of activation caused by decreased Coulombic repulsion. 15,19,20 In the case of complexes with large cavities (e.g.…”

“…14,15,19,20 Reducing the charge state mitigates extensive unfolding of the protein complexes (as observed from ion mobility data) and suppresses dissociation of the complexes, likely owing to the increased energy barrier of activation caused by decreased Coulombic repulsion. 15,19,20 In the case of complexes with large cavities (e.g. ring-like structures), compaction is observed prior to unfolding.…”