Development of a peptide probe for the occurrence of hydrogen (1H/2H) scrambling upon gas-phase fragmentation

TY - JOUR

T1 - Development of a peptide probe for the occurrence of hydrogen (1H/2H) scrambling upon gas-phase fragmentation

AU - Rand, Kasper Dyrberg

AU - Jørgensen, Thomas

PY - 2007

Y1 - 2007

N2 - Hydrogen (1H/2H) exchange combined with mass spectrometry (HX-MS) has become a valuable method for the analysis of protein structural dynamics. Currently, localization of the incorporated deuterons is made by enzymatic cleavage of the labeled proteins, and single-residue resolution is typically only achieved for a few residues. Determination of site-specific deuterium levels by gas-phase fragmentation would greatly increase the applicability of the HX-MS method. It is, however, mandatory for this gas-phase approach that hydrogen (1H/2H) scrambling in the gaseous peptide is negligible. Thus, it is important to have a simple reference system where the onset of scrambling processes is readily detected. Here we describe a simple well-characterized set of peptides with a unique regioselective labeling that ensures an inherent high sensitivity for the detection of scrambling. This selective labeling is achieved by utilizing differences in the intrinsic exchange rates between various amino acid residues. We demonstrate that our peptides can be infused directly into an electrospray ion source by means of a cooled glass syringe, while maintaining their selective labeling in solution. We further show that the selective labeling is completely erased upon low-energy collisional activation in a tandem mass spectrometry experiment as a result of extensive hydrogen (1H/2H) scrambling.

AB - Hydrogen (1H/2H) exchange combined with mass spectrometry (HX-MS) has become a valuable method for the analysis of protein structural dynamics. Currently, localization of the incorporated deuterons is made by enzymatic cleavage of the labeled proteins, and single-residue resolution is typically only achieved for a few residues. Determination of site-specific deuterium levels by gas-phase fragmentation would greatly increase the applicability of the HX-MS method. It is, however, mandatory for this gas-phase approach that hydrogen (1H/2H) scrambling in the gaseous peptide is negligible. Thus, it is important to have a simple reference system where the onset of scrambling processes is readily detected. Here we describe a simple well-characterized set of peptides with a unique regioselective labeling that ensures an inherent high sensitivity for the detection of scrambling. This selective labeling is achieved by utilizing differences in the intrinsic exchange rates between various amino acid residues. We demonstrate that our peptides can be infused directly into an electrospray ion source by means of a cooled glass syringe, while maintaining their selective labeling in solution. We further show that the selective labeling is completely erased upon low-energy collisional activation in a tandem mass spectrometry experiment as a result of extensive hydrogen (1H/2H) scrambling.

U2 - 10.1021/ac0710782

DO - 10.1021/ac0710782

M3 - Journal article

C2 - 17935303

SN - 0003-2700

VL - 79

SP - 8686

EP - 8693

JO - Industrial And Engineering Chemistry Analytical Edition

JF - Industrial And Engineering Chemistry Analytical Edition

IS - 22

ER -