Hydrogen/Deuterium Exchange Mass Spectrometry: A Mini-Tutorial

Transcription

1 Florida State University National High Magnetic Field Laboratory Tallahassee-Florida Hydrogen/euterium Exchange Mass Spectrometry: A Mini-Tutorial George Bou-Assaf 56 th ASMS Conference June 2 nd, 2008

2 Hydrogen Exchange : A Brief History Linderstrøm-Lang (1950 s): Amide hydrogen exchange rates should reflect the presence of hydrogen bonded structure Englander (1960 s) : studied H/T exchange by liquid scintillation (1980) improved the protocol by lowering the temperature of the separation step to reduce backexchange. Rosa & Richards (1979) : Spacial resolution enhancement by combination of proteolysis with HPLC Zhang and Smith (1993) : combined HX to MS, used FAB for ionization Johnson and Walsh (1994) : first to use ESI L.S. Busenlehner, R.N. Armstrong / Archives of Biochemistry and Biophysics 2005, 433, A.N. Hoofnagle, K.A.Resing, N.G.Ahn / Annu. Rev. Biophys. Biomol. Struct. 2003, 32:1-25

3 Advantages over NMR & X-Ray X-Ray Crystallography Crystallization problems Rigid systems Nuclear Magnetic Resonance Low sensitivity High concentration required Protein size < 50 ka

4 HX at the molecular level R H O R N H 3 N N COOH O R H Low exchange rates : α-helices, β-sheets and core of the protein. High exchange rates: Loops, turns and solvent accessible regions.

5 HX at the macromolecular level H/ exchange Quench Proteolysis Formation of a complex Comparison of deuteration level H/ exchange Quench Proteolysis Akashi, Satoko. Medicinal Research Reviews, 2006, 26(3),

6 Types of HX Thomas E. Wales, John R. Engen, Mass Spectrometry Reviews, 2006, 25,

7 Types of HX Thomas E. Wales, John R. Engen, Mass Spectrometry Reviews, 2006, 25,

8 Types of HX Off-exchange: it is hard to fully deuterate a protein, takes very long time On exchange is preferred E.A. Komives / International Journal of Mass Spectrometry 240, 2005,

9 Limitations of HX R H O R N H 3 N N COOH O R H Exchange in 2 O buffer while digestion, HPLC, MS in hydrogenated solvents and denaturing conditions. Use SFC 1, fast RPLC 2 Good sequence coverage Spatial resolution: multiple overlapping fragments. 1. M.R. Emmett, S. Kazazic, A.G. Marshall, W. Chen, S..H. Shi, B. Belaños and M.J. Greig, Anal. Chem. 2006, 78: G.M. Bou-Assaf, M.R. Emmett, A.G. Marshall, 56 th Amer. Soc. Mass Spectrom. Conf. on Mass Specrometry and applied topics 2008

10 Experimental Setup at NHMFL protein or complex dilute 10 fold w/ 2 O buffer H H H/ exchange Quench p 2.3 ~ 2.5 digest with active enzyme at ~1.0 o C Time (min) esalt ESI - MS Peptide separation Temp ~0 o C Jasco HPLC/SFC System

11 The exchange rate constant + k = k [ H ] + k [ OH ] ex H OH 8 and koh = 10 kh As temperature decreases, the exchange also decreases. We need enzymes that work in these conditions! PEPSIN PROTEASES TYPE XIII & TYPE XVIII avid L. Smith, JOURNAL OF MASS SPECTROMETRY, VOL. 32, 1997,

12 Peptide Mapping GSPEFGTGTRFGTLAKEAKKVHQTT RTVPAKRGTIYRNGVPIAEATSYNV YAVIENYKSATGKILYVEKTQFNKVA Sequence coverage: Pepsin : 93% Type XVIII : 84% Type XIII : 40% 99.7% Laetitia Cravello, Rapid Commun. Mass Spectrom. 2003; 17:

13 Spatial resolution Number of euteriums in Stated Rate Constant Range H Slower than 0.4 h -1 Zero H between 0.4 h -1 and 10 h -1 5 H Faster than 10 h -1 Apomyoglobin Segment F 43 KFKHLKTEAE 54 from protease type XIII Cleavage Log k (h -1 ) Apomyo SLOW MEIUM FAST Sequence 1 L F T G H P E T L E K F K F K H L K T E A E M Protease 2 F K F K H L K T E A E XIII 3 F K H L K T E Fragments 4 P E T L E K T L E K F K F K H Pepsin 6 E K F K F K H L K T E A E Fragments 7 E K F K F K H L K T E A E M L E K F Rate 9 1M+1S S S S S 4F + 1S 1F + 5S M Zhang H., Kazazic S., Schaub T.M., Tipton J.., Emmett M.R., and Marshall, A.G. (manuscript submitted)

14 Applications Folding and unfolding of proteins Influence of mutation on the 3 structures of proteins Thomas E. Wales, John R. Engen, Mass Spectrometry Reviews, 2006, 25, L.S. Busenlehner, R.N. Armstrong / Archives of Biochemistry and Biophysics 433 (2005) 34 46

15 Applications Conformational change induced by ligand binding Ligand : Ion, Metabolite or other Protein L.S. Busenlehner, R.N. Armstrong / Archives of Biochemistry and Biophysics 433 (2005) 34 46

16 Applications Molecular Mechanisms J. Lisal, T.T. Lam,.E. Kainov, M.R. Emmett, A.G. Marshall and R. Tuma / Nat. Struc. Mol. Biol. (2005) 12 (5): 34 46