Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (06): 1336-1343.doi: 10.3866/PKU.WHXB201303155

• BIOPHYSICAL CHEMISTRY • Previous Articles     Next Articles

Investigation of the Non-Covalent Interactions between Fragment Peptides of Bradykinin by Mass Spectrometry

CHEN Chen1, CHU Yan-Qiu1, DAI Xin-Hua2, FANG Xiang2, DING Chuan-Fan1   

  1. 1 Institute of Laser Chemistry, Department of Chemistry, Fudan University, Shanghai 200433, P. R. China;
    2 Chemical Metrology & Analytical Science Division, National Institute of Metrology, Beijing 100013, P. R. China
  • Received:2013-02-06 Revised:2013-03-14 Published:2013-05-17
  • Supported by:

    The project was supported by the National Science & Technology Pillar Program, China (2009BAK60B03) and National Major Scientific Instrument and Equipment Development Project, China (2011YQ090005).

Abstract:

To explore the important factors affecting the stability of gas phase bradykinin (R1P2P3G4F5S6P7F8R9), the non-covalent interactions between fragment peptides of bradykinin were investigated by electrospray ionization mass spectrometry (ESI-MS). The fracture sites are S6P7 (mode 1) and F5S6 (mode 2). The fragment peptides of bradykinin and its des-arginine analogues were synthesized. ESI-MS results showed that the fragment peptides of bradykinin obtained in the two modes can easily react by non-covalent interactions. In fracture mode 1, when R9 was removed, the peptide PF seldom bound to any other fragment peptide. While in fracture mode 2, non-covalent binding still occurred between fragment peptides when either R1 or R9 was removed, which indicates that serine is likely to be at the position of the β-turn. The collision induced dissociation (CID) revealed that the binding strength between RPPGFS and PFR, or RPPGF and SPFR, is stronger than for the peptides without R. For the complexes of RPPGFS with PFR, and RPPGF with SPFR, the binding constant (Kst) values determined by mass spectrometric titrations were 3.53×103 and 3.16×103, respectively, which are greater than the Kst value (1.25×103) of the complexes of PPGF with SPF. The mass spectrometric titrations confirmed the results from CID, indicating that the hydrogen bonds between the arginine residues of the two terminals of bradykinin play an important role in stabilizing the conformation of gas phase bradykinin.

Key words: Non-covalent interaction, Bradykinin, Fragment peptide, Mass spectrometry, Collision induced dissociation, Binding constant

MSC2000: 

  • O643