Protein Interactions Captured by Chemical Cross-linking: One-Step Cross-linking with Formaldehyde

2007 ◽  
Vol 2007 (8) ◽  
pp. pdb.prot4634-pdb.prot4634 ◽  
Author(s):  
O. W. Nadeau ◽  
G. M. Carlson
2021 ◽  
Author(s):  
Dmitri R. Davydov ◽  
Bikash Dangi ◽  
Guihua Yue ◽  
Bhagwat Prasad ◽  
Viktor G. Zgoda

This study aimed on exploration of the system-wide effects of the alcohol-induced increase in the content of cytochrome P450 2E1 (CYP2E1) in the human liver on drug metabolism. Using membrane incorporation of purified CYP2E1 modified with photoreactive crosslinkers benzophenone-4-maleimide (BPM) and 4-(N-succinimidylcarboxy)benzophenone (BPS), we explored the array of its protein-protein interactions (proteome) in human liver microsomes (HLM) with chemical cross-linking mass spectrometry (CXMS). Exposure of bait-incorporated HLM samples to light was followed by isolation of the His-tagged bait protein and its cross-linked aggregates on Ni-NTA agarose. Analyzing the individual bands of SDS-PAGE slabs of thereby isolated protein with the toolset of untargeted proteomics, we detected the cross-linked dimeric and trimeric complexes of CYP2E1 with other drug-metabolizing enzymes. Among the most extensively cross-linked partners of CYP2E1 are cytochromes P450 2A6, 3A4, 2C9, and 4A11. We also detected the conjugates of CYP2E1 with UDP-glucuronosyltransferases (UGTs) 1A6, 1A9, 2B4, 2B15, and 2B17. These results demonstrate the exploratory power of the proposed CXMS strategy and corroborate the concept of tight functional integration in the human drug-metabolizing ensemble through protein-protein interactions of the constituting enzymes. Of particular interest is the observation of efficient cross-linking of CYP2E1 with CYP4A11. This enzyme plays a central role in the synthesis of vasoactive eicosanoids and its interactions with alcohol-inducible CYP2E1 may shed light on the mechanisms of alcohol-induced hypertension.


2008 ◽  
Vol 8 (3) ◽  
pp. 409-420 ◽  
Author(s):  
Haizhen Zhang ◽  
Xiaoting Tang ◽  
Gerhard R. Munske ◽  
Nikola Tolic ◽  
Gordon A. Anderson ◽  
...  

2006 ◽  
Vol 11-12 ◽  
pp. 725-728
Author(s):  
Jun Hao Wu ◽  
Yoshitaka Ikarashi ◽  
Shuji Fujii ◽  
Seiichi Kawahara ◽  
Yoshinobu Isono

Loss tangent defined by the ratio of loss modulus to storage modulus, G”/G’, is widely used as a measure of energy loss for rubber materials. We can expect high loss tangent due to unstable state of polymer chains in large deformation. However, chemical cross-linking is usually introduced in no deformation where we cannot expect high loss tangent. Even if introduced in deformed state, polymer chains take relaxation before completion of cross-linking. In this study, hence, a novel two-step cure has been proposed. The loss tangent by two-step cure has been found to be higher than that by one-step cure in no deformation, showing effectiveness of the process proposed.


2017 ◽  
Vol 114 (7) ◽  
pp. 1732-1737 ◽  
Author(s):  
Devin K. Schweppe ◽  
Juan D. Chavez ◽  
Chi Fung Lee ◽  
Arianne Caudal ◽  
Shane E. Kruse ◽  
...  

Mitochondrial protein interactions and complexes facilitate mitochondrial function. These complexes range from simple dimers to the respirasome supercomplex consisting of oxidative phosphorylation complexes I, III, and IV. To improve understanding of mitochondrial function, we used chemical cross-linking mass spectrometry to identify 2,427 cross-linked peptide pairs from 327 mitochondrial proteins in whole, respiring murine mitochondria. In situ interactions were observed in proteins throughout the electron transport chain membrane complexes, ATP synthase, and the mitochondrial contact site and cristae organizing system (MICOS) complex. Cross-linked sites showed excellent agreement with empirical protein structures and delivered complementary constraints for in silico protein docking. These data established direct physical evidence of the assembly of the complex I–III respirasome and enabled prediction of in situ interfacial regions of the complexes. Finally, we established a database and tools to harness the cross-linked interactions we observed as molecular probes, allowing quantification of conformation-dependent protein interfaces and dynamic protein complex assembly.


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