The [Re, O8]+ potential energy surface: fourier transform ion cyclotron resonance collision induced dissociation studies and density functional calculations

1999 ◽  
Vol 185-187 ◽  
pp. 625-638 ◽  
Author(s):  
Martin Beyer ◽  
Christian Berg ◽  
Stefan Joos ◽  
Uwe Achatz ◽  
Wolfgang Hieringer ◽  
...  
2001 ◽  
Vol 7 (4-5) ◽  
pp. 393-398 ◽  
Author(s):  
Marjaana Nousiainen ◽  
Pirjo Vainiotalo ◽  
Xidong Feng ◽  
Peter J. Derrick

Dissociation of the complex between calmodulin, four calcium ions and the synthetic peptide RS20 derived from the phosphorylation site of smooth-muscle myosin light-chain kinase was studied by sustained off-resonance irradiation/collision-induced dissociation (SORI-CID)and electrospray ionisation (ESI)Fourier transform ion cyclotron resonance (FT-ICR)mass spectrometry. Gas-phase dissociation of isolated ions of calmodulin-RS20-Ca4 in the 8+ charge state yielded fragments via two parallel pathways; calmodulin-Ca4 complex ions in 5+ and 6+ charge states and RS20 ions in 2+ and 3+ charge states were detected at high resolution. The results are interpreted as indicating that RS20 binding to calmodulin in this complex is specific, involving particular non-covalent interactions that decompose readily during collision-induced dissociation. More specifically, it is proposed that the gas-phase dissociation of calmodulin-RS20-Ca4 complex reflects the existence in vacuo of salt bridges.


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